一个不太严谨的做法

dic={}

n=int(input())
for i in range(n):
    s=input().split()
    ss=''
    for j in range(1,len(s)):
        ss+=s[j]
    if s[0]=='add':
        dic[ss]=1
    else:
        if ss in dic:
            print('yes')
        else:
            print('no')

#include <bits/stdc++.h>
using namespace std;

unordered_map<string,int> um;

int main()
{
	int t;
	cin >> t;
	while(t--)
	{
		string op;
		cin >> op;
		if(op == "add")
		{
			string s;
			getline(cin,s);
			um[s]+=1;
		}
		else
		{
			string s;
			getline(cin,s);
			if(!um[s]) cout << "no" << endl;
			else cout << "yes" << endl;
		}
	}
}