//拉链法
#include <iostream>
#include <cstring>

using namespace std;

const int N = 100010;

int h[N], e[N], ne[N], idx = 0;

void insert(int x)      //数组模拟链表（邻接表）
{
    int k = (x % N + N) % N;    //防止负数
    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(e[i] == x)
        {
            return true;
        }
    }
    return false;
}

int main()
{

    memset(h, -1, sizeof h);

    int n;
    cin >> n;
    while(n--)
    {
        char c;
        cin >> c;
        if(c == 'I')
        {
            int x;
            cin >> x;
            insert(x);
        }
        if(c == 'Q')
        {
            int x;
            cin >> x;
            if(find(x)) cout << "Yes" << endl;
            else cout << "No" << endl;
        }
    }
    return 0;
}
//