#include <iostream>
#include <fstream>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int cinci=0,p,n,k,cinci1,i;
int v[]={0,5,25,125,625,3125,15625,78125,390625,1953125,9765625,48828125,244140625};
int main ()
{
    f>>p;
    if (p==0)
        g<<"1";
else
{
    while (k<p)
    {
        cinci+=5;
        cinci1=cinci;
		for (i=12;;i--)
			if (cinci1%v[i]==0)
			{
				k+=i;
				break;
			}
    }
    if (k==p)
        g<<cinci;
    else g<<"-1";
}
f.close();
g.close();
}