#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
#define Rep(i,a,b) for(register int i=(a);i<=int(b);++i)
#define Dep(i,a,b) for(register int i=(a);i>=int(b);--i)
#define rep(i,a,b) for(register int i=(a);i<int(b);++i)
#define mem(x,v) memset(x,v,sizeof(x))
#define fi first
#define se second
#define gc getchar
#define pc putchar
inline ll read(){
    ll x=0,f=1;char c=gc();
    for(;!isdigit(c);c=gc())if(c=='-')f=-1;
    for(;isdigit(c);c=gc())x=(x<<1)+(x<<3)+(c^48);
    return x*f;
}
inline void write(ll x){if(x<0)x=-x,pc('-');if(x>=10)write(x/10);putchar(x%10+'0');}
inline void wri(ll x){write(x);pc(' ');}
inline void writeln(ll x){write(x);pc('\n');}
int main(){
	int n,k;
	string s;
	cin >> n >> k >> s;
	string t = s;
	reverse(t.begin(),t.end());
	s += t;
	string mi = s;
	rep(i,0,n)
		mi = min(mi,s.substr(i,n));
	k--;
	while(k--){
		char c=mi[0];
		int cs=0;
		while(cs<n && mi[cs] == c) cs++;
		if(cs==n) break;
		mi = (mi.substr(0,cs) + mi).substr(0,n);
	}
	cout << mi << endl;
	return 0;
}