import java.io.*;

public class Main{
    static int N = 100010;
    static int[] h = new int[N];
    static int[] e = new int[N];
    static int[] ne = new int[N];
    static int idx;
    static void insert(int x){
        int k = (x%N+N)%N;
        e[idx] = x;
        ne[idx] = h[k];
        h[k] = idx++;
    }
    static boolean 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;
    }
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.valueOf(br.readLine());
        for(int i=0;i<N;i++){
            h[i]=-1;
        }
        while(n-->0){
            String[] s = br.readLine().split(" ");
            int x = Integer.valueOf(s[1]);
            if(s[0].equals("I")){
                insert(x);
            }else{
                if(find(x))    System.out.println("Yes");
                else    System.out.println("No");
            }
        }
    }
}

import java.io.*;

public class Main{
    static int N = 100003;
    static int[] h = new int[N];
    static int bound = (int)(1e9+1);
    static int find(int x){
        int k = (x%N+N)%N;
        while(h[k]!=bound && h[k]!=x){
            k++;
        }
        return k;
    }
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.valueOf(br.readLine());
        for(int i=0;i<N;i++){
            h[i]=bound;
        }
        while(n-->0){
            String[] s = br.readLine().split(" ");
            int x = Integer.valueOf(s[1]);
            int k = find(x);
            if(s[0].equals("I")){
                h[k]=x;
            }else{
                if(h[k]!=bound)    System.out.println("Yes");
                else    System.out.println("No");
            }
        }
    }
}