#include <algorithm>
#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
#define reps(i, a, n) for (ll i = (a); i < (ll)(n); ++i)
#define rep(i, n) reps(i, 0, n)
#define all(a) (a).begin(), (a).end()
#define is_integer(x) floor(x) == x
// なんかstd::vector<bool>の挙動を修正できるやつ

/* alias */
using ull = unsigned long long;
using ll = long long;
using vi = vector<int>;
using vl = vector<long>;
using vll = vector<long long>;
using vvi = vector<vi>;
using vvl = vector<vl>;
using vvll = vector<vll>;
using vs = vector<string>;
using pii = pair<int, int>;
//clang-format off
#define debug(x)                                                               \
  cerr << "\033[33m(line:" << __LINE__ << ") " << #x << ": " << x << "\033[m"  \
       << endl;

//clang-format on


int main() {
  string s,t;
  int n;
  cin >> s >> t >> n;
  cout << s;
  rep(i,n){
    cout << "_" << t;
  }
  cout << endl;


}