#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int main() {
	int n = ri();
	int k = ri();
	std::string s;
	std::cin >> s;
	int one = k - 1;
	int left = n - one;
	int count = left / 2;
	
	std::string res;
	for (int i = 0; i < count; i++) res.push_back(s[one + i * 2]), res.push_back(s[one + i * 2 + 1]);
	if (left & 1) res.push_back(s[one + left - 1]), std::reverse(s.begin(), s.begin() + one);
	std::cout << res << std::string(s.begin(), s.begin() + one) << std::endl;
	return 0;
}