#include <bits/stdc++.h>
using namespace std;
string Process(string s) {
  int n = s.size();
  int i = n - 1;
  while (i - 1 >= 0 && s[i - 1] == s[i]) i--;
  string w = s;
  reverse(w.begin(), w.end());
  s += w;
  return s.substr(i, n);
}
string Process(string s, int k) {
  for (int i = 0; i < k; ++i) {
    s = Process(s);
  }
  return s;
}
int main() {
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  if (k > 20) {
    k = 20;
  }
  string result = "";
  string w = s;
  reverse(w.begin(), w.end());
  string ss = s + w;
  for (int i = 0; i <= n; ++i) {
    string cur = ss.substr(i, n);
    cur = Process(cur, k - 1);
    if (result == "" || result > cur) {
      result = cur;
    }
  }
  cout << result << endl;
  return 0;
}
