#include <fstream.h>
int main(){
	unsigned long p,k,i,aux;
	ifstream f("fact.in");
	ofstream g("fact.out");
	f>>p;
	if(p>0){
		i=5;k=0;
		while(k<p){
                	aux=i;
		      while(aux%5==0){
			aux/=5;k++;
		      }
		      i+=5;
		}
		if(k==p)
			g<<i-5;
		else
			g<<-1;
	}else
		g<<1;
	return 0;
}