#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+3;
int n;
int h[N],e[N],ne[N],idx;
void insert(int x){
    int k = (x%N+N)%N;
    //这里是e[idx]=x，不是e[idx]=k
    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;i=ne[i]){
        //这里是e[idx]=x，不是e[idx]=k
        if(e[i]==x)return true;
    }
    return false;
}
int main(){
    cin>>n;
    //-1代表空节点
    memset(h,-1,sizeof h);
    for(int i = 1;i<=n;i++){
        char ch;int x;
        cin>>ch>>x;
        if(ch=='I')insert(x);
        else{
            if(find(x))cout<<"Yes"<<endl;
            else cout<<"No"<<endl;
        }
    }
    return 0;
}