#include<stdio.h>
long long p,i,nr2,nr5,ci;
int fact()
{
for(i=1;;i++)
	{
	 ci=i;

	 while(ci%2==0)
		 nr2++,ci/=2;

	 while(ci%5==0)
		 nr5++,ci/=5;
	 if((nr2==p&&nr2<nr5)||(nr5==p&&nr5<nr2))return i;
	 if(nr2>p&&nr5>p)return -1;
	}
}



int main()
{
freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);

scanf("%lld",&p);
printf("%d",fact());
return 0;
}