#include <cstdio>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;

#define R register

int N, K;
string s, rev, tmp, str;

int main() {
	cin >> N >> K >> s;
	rev = s, reverse(rev.begin(), rev.end());
	tmp = s + rev, reverse(tmp.begin(), tmp.end());
//cout << tmp << endl;
	str = tmp.substr(0, N);
	for(R int i = 1; i < N; ++i) {
		rev = tmp.substr(i, N);
		if(rev < str) str = rev;
	}
	reverse(str.begin(), str.end());
//cout << str << endl;
	for(R int i = 1, j, k; i < K; ++i) {
		for(j = N - 2; ~j; --j) if(str[j] != str[N - 1]) break;
		str = str + str.substr(j + 1, N);
//cout << str << endl;
		k = str.length();
		str = str.substr(k - N, N);
		if(j == -1) break;
//cout << str << endl;
	}
	reverse(str.begin(), str.end());
 	cout << str;
 	return 0;
}
