#include<stdio.h>
int main(){
	int n,p,i,d;
	freopen("fact.in","r",stdin);
	freopen("fact.out","w",stdout);
	scanf("%d",&p);
	if(p==0)
		n=1;
	else
	    if(p>=1){
		i=1;
		n=5;
		while(i<=p){
			d=n;
			while(d%5==0){
				d=d/5;
				i++;
			}
			n=n+5;
		}}
		else
			n=-1;
	printf("%d\n",n-5);
	fclose(stdin);
	fclose(stdout);
	return 0;
}