#include<stdio.h>
#define fscnaf fscanf
FILE *f,*g;

long p,i,aux;
int main()
{
	f=fopen("fact.in","r");
	g=fopen("fact.out","w");
	fscnaf(f,"%ld",&p);
	if(p==0)
	{
		fprintf(g,"1\n");
		return 0;
	}
	for(i=5;;i += 5)
	{
		aux=i;
		while(aux%5==0)
		{
			aux/=5;
			p--;
		}
		if(p<0)
		{
			fprintf(g,"-1\n");
			return 0;
		}
		if(p==0)
		{
			fprintf(g,"%ld\n",i);
			return 0;
		}
	}
	return 0;
}