#include<bits/stdc++.h>
using namespace std;
const int N = 2e5+3,null = 0x3f3f3f3f;
int n;
int h[N];
int find(int x){
    int k = (x%N+N)%N;
    //遇到空或者相等就停止循环，返回此时的下标位置即可
    while(h[k]!=null&&h[k]!=x){
        k++;
        if(k==N)k=0;
    }
    return k;
}
int main(){
    cin>>n;
    //-1代表空节点
    memset(h,0x3f,sizeof h);
    for(int i = 1;i<=n;i++){
        char ch;int x;
        cin>>ch>>x;
        if(ch=='I')h[find(x)]=x;
        else{
            //如果相等，说明出现过
            if(h[find(x)]==x)cout<<"Yes"<<endl;
            else cout<<"No"<<endl;
        }
    }
    return 0;
}