#include <fstream>

using namespace std;


int factorial(int p)
{
	if (p < 0)
		return -1;
	else if (p == 0)
		return 1;

	int n = 5, aux, nr = 0;
	bool multipluZece = false;

	while (1)
	{
		aux = n;

		if (multipluZece == true)
		{
			while (aux % 10 == 0)
			{
				nr ++;
				aux /= 10;
			}

			multipluZece = false;
		}
		else
		{
			while (aux % 5 == 0)
			{
				nr ++;
				aux /= 5;
			}

			multipluZece = true;
		}

		if (nr > p)
			return -1;
		else if (nr == p)
			return n;
		
		n += 5;
	}
}


int main(int argc, char** argv)
{
	int p;
    
    ifstream in("factorial.in");
    ofstream out("factorial.out");
    
    in >> p;
    out << factorial(p);

    in.close();
	out.close();
    
	return 0;
}