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

#define ll long long
#define MOD 998244353

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