#include<cstdio>
long long n;

void cit()
{
	scanf("%d",&n);
}

void rez()
{
	int i,j;
	long long nr=0;
	if(n==0)
		printf("0");
	else if(n==1)
			printf("5");
	else
	{
	for(i=5; nr<n; i+=5)
	{
		int p;
		j=i;
		while(!(j%5))
		{
			nr++;
			j/=5;
		}
		
	}
	
	if(nr==n)
		printf("%lld\n", i-5);
	else
		printf("-1\n");
}
}		
		

int main()
{
	freopen("fact.in","r",stdin);
	freopen("fact.out","w",stdout);
	
	cit();
	rez();
	
	return 0;
}