#include <bits/stdc++.h>
using namespace std;
const int N = 200003;
const int INF = 0x3f3f3f3f;
int h[N];
int find(int x) {
    int k = (x % N + N) % N;
    while (h[k] != INF && h[k] != x) {
        k++;
        if (k == N) k = 0;
    }
    return k;
}
int main() {
    int n;
    cin >> n;
    memset(h, 0x3f, sizeof h);
    while (n--) {
        string op;
        int x;
        cin >> op >> x;
        int k = find(x);
        if (op == "I")h[k] = x;
        else {
            if (h[k] != INF) puts("Yes");
            else puts("No");
        }
    }
    return 0;
}