#include <bits/stdc++.h>
using namespace std;
char t[105];
int n, k;
int nxt[105];
inline void get(char *s, int nxt[]) {
  nxt[0] = nxt[1] = 0;
  for (int i = 1; i < n; i++) {
    int j = nxt[i];
    while (j && t[i] != t[j]) j = nxt[j];
    if (t[j] == t[i])
      nxt[i + 1] = j + 1;
    else
      nxt[i + 1] = 0;
  }
}
int main() {
  cin >> n >> k;
  cin >> t;
  get(t, nxt);
  cout << t;
  for (int i = 1; i < k; i++)
    for (int j = nxt[n]; j < n; j++) cout << t[j];
  return 0;
}
