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

const int N = 1e5;
int n,m,k;
string x,y;
map<string,string> father;

string findf(string i){
    if(father[i] == i)){//这一行为什么会报错？
        return i;
    }
    return father[i] = findf(father[i]);
}