#include<stdio.h>
int main(){
	FILE*in=fopen("fact.in","r");
	FILE*out=fopen("fact.out","w");
	int p,n=0,n1,i=0;
	fscanf(in,"%d",&p);
	fclose(in);
	if(p==0){
		fprintf(out,"1\n");
		return 0;
	}
	while(i<p){
		n=n+5;
		n1=n;
		while((n1%5==0)&&(n1!=0)){
			n1=n1/5;
			i++;
		}
	}
	if(i==p)
		fprintf(out,"%d\n",n);
	if(i>p)
		fprintf(out,"-1\n");
	fclose(out);
	return 0;
}