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

#ifdef local
#include "debug.hpp"
#else
#define debug(...) ;
#endif

int main(void) {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    constexpr char endl = '\n';

    string s, t;
    int n;
    cin >> s >> t >> n;

    string ans = s;
    for (int i = 0; i < n; i++) {
        ans.push_back('_');
        ans += t;
    }
    
    cout << ans << endl;

    return 0;
}