#include<stdio.h>
int main ()
{
freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);
long long p,i,ci;
scanf("%I64d",&p);
if(p!=0)
for(i=5;i<=2000000000000;i+=5)
	{ci=i;
	while(ci%5==0)
		{p--;
		ci/=5;
		}
	if(p==0)
		{printf("%I64d",i);
		break;
		}
	if(p<0)
		{printf("-1");
		break;
		}
	}
else
	printf("1");
return 0;
}