#include <bits/stdc++.h>
using namespace std;
const int N = 5001, K = 18;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, k, i, j;
  string s, ans, ss, rs, cs;
  cin >> n >> k >> s;
  if (k > K) {
    j = 0;
    for (i = 1; i < n; i++)
      if (s[i] < s[j]) j = i;
    for (i = 0; i < n; i++) cout << s[j];
    cout << '\n';
  }
  ans = s;
  for (i = 0; i < k; i++) {
    rs = s;
    reverse(rs.begin(), rs.end());
    ss = s + rs;
    cs = ss.substr(0, n);
    ans = cs;
    s = cs;
    reverse(s.begin(), s.end());
    for (j = 1; j + n <= ss.size(); j++) {
      cs = ss.substr(j, n);
      if (cs < ans) ans = cs;
      reverse(cs.begin(), cs.end());
      if (cs < s) s = cs;
    }
    reverse(s.begin(), s.end());
  }
  cout << ans << '\n';
}
