#include <stdio.h>
#include <math.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <numeric>
#include <string>
#include <map>
#include <stack>
using namespace std;
typedef long long int lli;
#define urept(soeji, start, n) for (int soeji = start; soeji < n; soeji++)
#define drept(soeji, start, n) for (int soeji = start; soeji > n; soeji--)
int main(void)
{
    int N, K;
    cin >> N >> K;
    string s;
    cin >> s;
    for (int i = 0; i < N - K + 1; i++)
    {
        //reverse(s.begin() + i, s.begin() + (i + K));
        swap(s[i], s[i + K - 1]);
    }
    cout << s << endl;
    return 0;
}