#include<iostream>
#include<fstream>

using namespace std;

int main(){
int n,p,m;
	ifstream fin("fact.in");
	fin>>p;
	ofstream fout("fact.out");
	if (p==0)
		fout<<"1";
	else{
		bool ver;
		ver=true;
		n=5;
		m=305175781;
		while ((m>5)&&(ver)){
			if ((p+1)%m==0)
				ver=false;
			p-=(p/m);
			m=(m-1)/5;
		}
		if (ver)
			fout<<p*5;
		else
			fout<<"-1";
	}
	fout.close();
	return 0;
}