#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 500;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int BASE = 31337;
string S;
int k, n;
int main() {
  cin >> n >> k >> S;
  for (int i = 0; i < k; i++) {
    string U = S;
    reverse(S.begin(), S.end());
    U += S;
    for (int i = 1; i <= n; i++) {
      if (U.substr(i, n) < S) S = U.substr(i, n);
    }
    if (i != k - 1) reverse(S.begin(), S.end());
    bool gotov = 1;
    for (char c : S) gotov &= (c == S[0]);
    if (gotov) break;
  }
  cout << S << endl;
  return 0;
}
