#include <stdio.h>
int main()
{
	int n,p,k;
	FILE *f=fopen("fact.in","r");
	FILE *g=fopen("fact.out","w");
	n=0;
	fscanf(f,"%d",&p);
	if (p==0){fprintf(g,"1\n");}
	else
	{
	while (p>0)
	{
		n=n+5;
		k=n;
		while (k%5==0)
		{
			k=k/5;
			p=p-1;
		}
	}
	if (p==0){fprintf(g,"%d\n",n);}
	else {fprintf(g,"-1\n");}}
	fclose(f);
	fclose(g);
	return 0;
}