#include <iostream>
#include <cstring>

using namespace std;

const int N = 200003, null = 0x3f3f3f3f;

int h[N];

int find(int x)
{
    int k = (x % N + N) % N; // 初始想要找的位置

    while (h[k] != null && h[k] != x) // 没有就往后走，一定要找到坑位或者和h[k] == x;
    {
        k ++;
        if (k == N) k = 0; 
    }

    return k;
}

int main()
{
    int n;
    scanf("%d", &n);

    memset(h, 0x3f, sizeof h);

    while (n --)
    {
        char op[2];
        int x;
        scanf("%s%d", op, &x);

        int k = find(x);
        if (op[0] == 'I') h[k] = x;
        else 
        {
            if (h[k] != null) puts("Yes");
            else puts("No");
        }

    }

    return 0;
}