#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  string s;
  cin >> n >> k >> s;
  k = min(k, 15);
  for (int i = 0; i < (k - 1); i++) {
    s = s + s;
    reverse(s.begin() + n, s.end());
    string t = "~";
    for (int j = 0; j < (n); j++) {
      string tmp = s.substr(j, n);
      reverse(tmp.begin(), tmp.end());
      t = min(t, tmp);
    }
    reverse(t.begin(), t.end());
    s = t;
  }
  string ans = "~";
  s = s + s;
  reverse(s.begin() + n, s.end());
  for (int j = 0; j < (n); j++) ans = min(ans, s.substr(j, n));
  cout << ans << '\n';
  return 0;
}
