#include <cstdint>
#include <iostream>
typedef int64_t Int;

int main() {
	const int N = 5000;
	Int b[N+1], c[N+1], d[N+1];
	
	for (int k = 0; k <= 1; k++) b[k] = 1;
	for (int n = 2; n <= N; n++) b[n] = 1 + b[n-2];
	for (int k = 0; k <= 2; k++) c[k] = b[k];
	for (int n = 3; n <= N; n++) c[n] = b[n] + c[n-3];
	for (int k = 0; k <= 4; k++) d[k] = c[k];
	for (int n = 5; n <= N; n++) d[n] = c[n] + d[n-5];
	
	std::cout << d[N] << std::endl;
	
	return 0;
}