#include <cstring>
#include <iostream>
using namespace std;
const int N = 200003, null = 0x3f3f3f3f;
int h[N];
int find(int x) {
int k = (x % N + N) % N;
while (h[k] != null && h[k] != x) {
k++;
if (k == N) k = 0;
}
return k;
}
int main() {
int n;
cin >> n;
memset(h, 0x3f, sizeof h);
while (n--) {
char op[2];
int x;
cin >> op >> x;
int k = find(x);
if (*op == 'I') {
h[k] = x;
}
else {
if (find(x)) puts("Yes");
else puts("No");
}
}
}