#include<iostream>
#include<algorithm>
#include<cstring>

using namespace std;

const int N = 100010;
int h[N], hp[N], ph[N], cnt;

void heap_swap(int a, int b) {
    swap(ph[hp[a]], ph[hp[b]]);
    swap(hp[a], hp[b]);
    swap(h[a], h[b]);
}

void down(int u) {
    int t = u;
    if (u * 2 <= cnt && h[u * 2] < h[t])t = u * 2;
    if (u * 2 + 1 <= cnt && h[u * 2 + 1] < h[t])t = u * 2 + 1;
    if (u != t) {
        heap_swap(u, t);
        down(t);
    }
}

void up(int u) {
    while (u / 2 && h[u] < h[u / 2]) {
        heap_swap(u, u / 2);
        u >> 1;
    }
}

int main() {
    ios::sync_with_stdio(false);
    int n, m = 0;
    cin >> n;
    while (n--) {
        char op[5];
        int k, x;
        cin >> op;
        if (!strcmp(op, "I")) {
            cin >> x;
            ph[++m] = ++cnt, hp[cnt] = m, h[cnt] = x;
            up(cnt);
        } else if (!strcmp(op, "PM"))printf("%d\n", h[1]);
        else if (!strcmp(op, "DM")) {
            heap_swap(1, cnt);
            cnt--;
            down(1);
        } else if (!strcmp(op, "D")) {
            cin >> k;
            k = ph[k];
            heap_swap(k, cnt);
            cnt--;
            down(k), up(k);
        } else {
            cin >> k >> x;
            k = ph[k];
            h[k] = x;
            down(k), up(k);
        }
    }
    return 0;
}