#include<stdio.h>

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

	long long unsigned aux,p,n,nr5=0;

	scanf("%llu ",&p);

	for(n=4*p;n<=5*p;n++)

	{	aux=n;

		nr5=0;

		while(aux)

		{	nr5+=aux/5;

			aux/=5;

		}


		if(nr5==p)

		{	printf("%llu ",n);

			return 0;

		}

		else

			if(nr5>p)

			{	printf("-1");

				return 0;

			}

	}

	printf("-1");

	return 0;

}