#include<iostream>
#include<cstring>
using namespace std;

const int N = 100013;
int h[N], ne[N], e[N];
int idx = 0;
int n, x;
char opt;

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 != -1; i = ne[i]) {
        if (x == e[i]) return true;
    }
    return false;
}

int main() {
    cin >> n;
    memset(h, -1, sizeof h);
    while (n -- ) {
        cin >> opt;
        if (opt == 'I') {
            cin >> x;
            insert(x);
        }
        else if (opt == 'Q') {
            cin >> x;
            if (find(x)) cout << "Yes" << endl;
            else cout << "No" << endl;
        }

    }

}