#include <fstream.h>
#include <math.h>
int main(){
	unsigned long p,i,aux,k;

	ifstream f("fact.in");
	ofstream g("fact.out");
	f>>p;
	if(p<=pow(10,8))
		if(p>=1){
			k=0;
			i=5;
			while(k<p){
				if(i%5==0){
					aux=i;
					while(aux%5==0){
						aux/=5;
						k++;
					}
				}
				i+=5;
			}
			g<<i-5;
		}else
			g<<1;
	else
		g<<-1<<endl;
	return 0;
}