#include <algorithm>
#include <array>
#include <cstdio>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

#define N 5 // Assumed positive number smaller than str.size()

int main() {
	const string str("atgctgttg");
	const int n1 = N - 1;
	vector<array<char, N>> result(str.size() - n1);

	transform(str.cbegin(), str.cend() - n1, result.begin(), [](const auto& i) {
		array<char, N> result;

		copy_n(&i, N, result.begin());
		return result;
	});

	for (auto& i : result) {
		printf("%.*s\n", N, &i);
	}
}