#include <fstream>

using namespace std;

ifstream in("fact.in");
ofstream out("fact.out");

int main()
{
	int p, n;
	in >> p;
	n = p * 5;
	if (p == 0)
		out << 1;
	else if (p < 0)
		out << -1;
	else
		out << n;
}