#include <cstdio>
using namespace std;
int main()
{
	freopen("fact.in","r",stdin);
	freopen("fact.out","w",stdout);
	
	unsigned long long int x;
	int p,q=1,t;
	scanf ("%d",&p);
	while (t<p)
	{
		x=1;
		for (int i=q;i<q+5;i++)
			x*=i;
		while (x%10==0)
		{
			x/=10;
			t++;
		}
		q+=5;
	}
	
	if (t==p)
		printf ("%d \n",q-1);
	else
		printf ("-1 \n");

}