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

const int N=2e5+3;
int h[N],null=0x3f3f3f3f;


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 c;
        int x;
        cin>>c>>x;
        int t=find(x);
        if(c=='I')h[t]=x;
        else {
            if(h[t]==x)cout<<"Yes"<<endl;
            else cout<<"No"<<endl;
        }
    }
}