#include <bits/stdc++.h>
using namespace std;
char a[52];
int kmp[52];
int main() {
  int j, i, n, m;
  scanf("%d%d%s", &n, &m, a + 1);
  j = 0;
  for (i = 2; i <= n; ++i) {
    while (j && a[i] != a[j + 1]) j = kmp[j];
    if (a[j + 1] == a[i]) j++;
    kmp[i] = j;
  }
  for (i = 1; i <= kmp[n]; ++i) printf("%c", a[i]);
  for (i = 1; i <= m; ++i)
    for (j = kmp[n] + 1; j <= n; ++j) printf("%c", a[j]);
  return 0;
}
