#include <cstdio>   
#include <map> 
#include <string> 


using namespace std; 

char S1[15], S2[45]; 
map<string,int> M; 


int main(){  
    int n;  
    scanf("%d",&n);  
    while(n--){  
        scanf("%s%s", S1, S2); 
        string s2 = S2; 
        map<string,int>::iterator it; 
        
        if(S1[0]=='i'){ 
            M[s2]++; 
        } 
        else if(S1[0] == 's'){ 
            string s2 = S2; 
            int flag = 0; 
            for(it = M.lower_bound(S2); it != M.end(); it++){  
                string t = it->first;  
                if(t.find(s2) != 0)  
                    break;  
                if(it->second) {
                    flag = 1;  
                    break;  
                }  
            }  
            puts(flag?"Yes":"No");  
        }  
        else{  
            for(it = M.lower_bound(S2); it != M.end(); it++){  
                string f = it->first;  
                if(f.find(s2) != 0)  
                    break;  
                it -> second=0;  
            }  
        }  
    }  
    return 0;  
}