#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    string s, t;
    int n;
    cin >> s >> t >> n;
    t = '_' + t;
    for (int i = 0; i < n; i++){
        s += t; 
    }
    cout << s << endl;
}