#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;

typedef long long ll;

int main() {
    int N, K;
    string S;
    cin >> N >> K >> S;
    rep(i, N - K + 1) cout << S[i + K - 1];
    if ((N - K + 1) % 2) {
        rep(i, K - 1) cout << S[K - 2 - i];
    } else {
        rep(i, K - 1) cout << S[i];
    }
    cout << "\n";
}