using namespace std;
#include<fstream>
int main(){
	ifstream f("fact.in");
	ofstream g("fact.out");
	long long a, c, p, b, r, s;
	f>>p;
	a=4*p+1;
	b=a/5;
	c=a-5*b;
	if (c!=0) a=a+5-c;
	s=0;
	while (s==0){
	c=5;
	r=0;
	while (c<=a){
		r=r+a/c;
		c=c*5;
	}
	if (r>p) {g<<"-1"; s=1;}
	else 
	if (r==p) { g<<a; s=1;}
	a=a+5;
	}
	return 0;
}