#include <bits/stdc++.h>

using namespace std;
const int N = 100003;
int h[N];
int e[N], ne[N], idx;
void insert(int x) {
    int k = (x % N + N) % N;
    e[idx] = x, ne[idx] = h[k], h[k] = idx++;
}
bool find(int x) {
    int k = (x % N + N) % N;
    for (int i = h[k]; ~i; i = ne[i])
        if (e[i] == x) return true;
    return false;
}
int main() {
    int n;
    cin >> n;
    memset(h, -1, sizeof h);
    while (n--) {
        string op;
        int x;
        cin >> op >> x;
        if (op == "I") insert(x);else {if (find(x)) puts("Yes");else puts("No");}}
    return 0;
}