#include "stdio.h"

long long p;
long long i;
long long m;
long long nr;

int main()
{
	freopen("factorial.in","r",stdin);
	freopen("factorial.out","w",stdout);
	scanf("%lld",&p);
	if(p==0)
	{	
		printf("1");
		return 0;
	}
	for(i=5;nr<p;i+=5)
	{
		m=i;
		while(m%5==0)
		{
			m/=5;
			nr++;
		}
	}
	if(nr==p)
		printf("%lld",i-5);
	else
		printf("-1");
	return 0;
}