#include<fstream>
using namespace std;
unsigned int n,x,p5,nr;
int main()
{
	ifstream f("fact.in");
	ofstream g("fact.out");
	f>>n;
	if(n==0)
		g<<1;
	else
	{
		x=5;
		p5=1;
		while(p5<n)
		{
			x+=5;
			nr=x;
			while(nr%5==0)
			{
				p5++;
				nr/=5;
			}
		}
		if(p5==n)
		g<<x;
		else
			g<<-1;
		
	}
	return 0;
}