#include <bits/stdc++.h>
using namespace std;
int n, k;
string s;
int main() {
  ios::sync_with_stdio(0);
  cin >> n >> k >> s;
  while (k--) {
    string lst = s, u = s;
    reverse(s.begin(), s.end()), u.append(s);
    for (int i = 0; i + n - 1 < u.length(); i++) {
      s = min(s, u.substr(i, s.length()));
    }
    if (s == lst) {
      cout << s << endl;
      return 0;
    }
    if (k) reverse(s.begin(), s.end());
  }
  cout << s << endl;
  return 0;
}
