#include<iostream>
#include<fstream>
#include<math.h>
using namespace std;

int zero (int n)
{
	int uc,k=0;
	while(n!=0)
	{
		uc=n%10;
		if(uc!=0)
			return 0;
		else k++;
		n=n/10;
	}
	return k;
}
int main()
{
	ifstream f("fact.in");
	ofstream g("fact.out");
	
	double aux,p;
	int n2,n=1,i,ok=0;
	f>>p;
	aux=pow(10, p);
	while(ok==0)
	{
		n2=1;
		for(i=1;i<=n;i++)
			n2=n2*i;
		cout<<n;
		if(zero(n2)==p)
			ok=1;
		n++;
	}
if(ok==1)
	g<<n;
else g<<-1;

return 0;
}