#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, l = 0;
  string t;
  cin >> n >> k >> t;
  for (int i = 1; i < t.size(); ++i) {
    if (t[i] == t[0]) {
      bool b = 1;
      for (long long j = i + 1; j < t.size(); ++j) {
        if (t[j] != t[j - i]) {
          b = 0;
          break;
        }
      }
      if (b) {
        l = t.size() - i;
        break;
      }
    }
  }
  cout << t;
  for (int i = 1; i < k; ++i) {
    for (long long j = l; j < t.size(); ++j) {
      cout << t[j];
    }
  }
  cout << endl;
  return 0;
}
