#include <bits/stdc++.h>

using namespace std;
const int N = 100010;
int n;
struct Node {
    int st;
    int ed;
    const bool operator<(const Node &W) {
        return ed < W.ed;
    }
} w[N];

/*
5
1 2 4 6 8
3 5 7 9 10

答案：
3
*/
int main() {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> w[i].st;
    for (int i = 0; i < n; i++) cin >> w[i].ed;
    sort(w, w + n);
    int ans = 0, t = 0; // 设置的个数，前一个的结束时间

    for (int i = 0; i < n; i++) {
        if (w[i].st > t) {
            t = w[i].ed;
            ans++;
        }
    }
    cout << ans << endl;
    return 0;
}