#include <iostream>
#include <fstream>
std::ifstream f("fact.in");
std::ofstream g("fact.out");

int findTrailingZeros(int n)
{
	// Initialize result 
	int count = 0;

	// Keep dividing n by powers of  
	// 5 and update count 
	for (int i = 5; n / i >= 1; i *= 5)
		count += n / i;

	return count;
}

int main()
{
	int p;
	f >> p;
	
	if (p == 0) {
		g << "1";
		return 0;
	}
		
	int n = 5;
	while (1)
	{
		int count = findTrailingZeros(n);

		if (count == p) {
			g << n;
			return 0;
		}
		if (count > p) {
			g << "-1";
			return 0;
		}

		n+=5;
	}
}