#include <bits/stdc++.h>
using namespace std;
int n;
string best;
bool compare(string x, bool reversed) {
  for (int i = 0; i < n; i++) {
    if (!reversed && x[i] != best[i]) return x[i] < best[i];
    if (reversed && x[n - 1 - i] != best[n - 1 - i])
      return x[n - 1 - i] < best[n - 1 - i];
  }
  return true;
}
int main() {
  int k;
  string s;
  cin >> n >> k >> s;
  for (int i = 0; i < k; i++) {
    string t = s;
    reverse(t.begin(), t.end());
    s += t;
    best = string(n, 'z');
    for (int j = 0; j <= n; j++) {
      string now = s.substr(j, n);
      if (compare(now, i != k - 1)) best = now;
    }
    if (best == s) {
      cout << best << endl;
      return 0;
    }
    s = best;
  }
  cout << s << endl;
  return 0;
}
