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