#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18;
const int inf = 1e9, dx[] = {0, 0, 1, -1, 1, -1, 1, -1},
          dy[] = {1, -1, 0, 0, 1, 1, -1, -1}, MOD = 1e9 + 7;
long double eps = 1e-7, pi = acos(-1);
int n, k, cnt;
string t, s;
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> k >> t;
  for (int i = 1; i < n; i++)
    if (t.substr(0, i) == t.substr(n - i, i)) cnt = i;
  cout << t;
  for (int i = 1; i < k; i++) cout << t.substr(cnt, n - cnt);
  return 0;
}
