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#include <cstdio>
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#include <iostream>
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#include <vector>
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#include <algorithm>
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#include <cstring>
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using namespace std;
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// 无法AC
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const int N = 1e5 + 7;
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struct Node {
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int l, r;
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int color; // 哪种颜色的海报
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int tag; // 表示这个区间的数被修改了为同一个数
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} tr[N << 4];
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int T, n;
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int l[N], r[N];
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int vis[N], ans;
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int b[N], bl; // 离散化数组
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void build(int u, int l, int r) {
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tr[u].l = l, tr[u].r = r;
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tr[u].color = 0;
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tr[u].tag = -1;
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if (l == r) return;
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int mid = (l + r) >> 1;
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build(u << 1, l, mid);
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build(u << 1 | 1, mid + 1, r);
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}
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void pushup(int u) {
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if (tr[u].tag) {
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tr[u << 1].color = tr[u].color;
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tr[u << 1 | 1].color = tr[u].color;
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tr[u << 1].tag = tr[u << 1 | 1].tag = 1;
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tr[u].tag = 0;
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}
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}
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void modify(int u, int l, int r, int x) {
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if (l <= tr[u].l && r >= tr[u].r) {
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tr[u].color = x;
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tr[u].tag = 1;
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return;
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}
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pushup(u);
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int mid = (tr[u].l + tr[u].r) >> 1;
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if (l <= mid) modify(u << 1, l, r, x);
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if (r > mid) modify(u << 1 | 1, l, r, x);
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}
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void query(int u, int l, int r) {
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if (tr[u].tag == -1) return;
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if (tr[u].tag) {
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if (!vis[tr[u].color] && tr[u].color) {
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++ans;
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vis[tr[u].color] = 1;
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}
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return;
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}
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int mid = (l + r) >> 1;
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query(u << 1, l, r);
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query(u << 1 | 1, l, r);
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}
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/*
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答案：
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4
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*/
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int main() {
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#ifndef ONLINE_JUDGE
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freopen("P3740.in", "r", stdin);
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#endif
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// 加快读入
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ios::sync_with_stdio(false), cin.tie(0);
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cin >> T;
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while (T--) {
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cin >> n;
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ans = 0;
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memset(vis, 0, sizeof vis);
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memset(tr, 0, sizeof tr);
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bl = 0;
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for (int i = 1; i <= n; i++) {
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cin >> l[i] >> r[i];
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b[++bl] = l[i];
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b[++bl] = r[i];
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b[++bl] = r[i] + 1; // 区间覆盖问题，为防止缝隙问题，需要r+1也入离散化数组
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}
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sort(b + 1, b + 1 + bl);
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int tot = unique(b + 1, b + 1 + bl) - b - 1;
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build(1, 1, tot);
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int cnt = 0;
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for (int i = 1; i <= n; i++) {
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l[i] = lower_bound(b + 1, b + 1 + bl, l[i]) - b;
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r[i] = lower_bound(b + 1, b + 1 + bl, r[i]) - b;
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modify(1, l[i], r[i], ++cnt);
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}
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query(1, 1, tot);
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printf("%d\n", ans);
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}
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return 0;
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}
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