#include <iostream>
#include <fstream>
#include <cmath>
#include <algorithm>
using namespace std;
 
ifstream f("fact.in");
ofstream g("fact.out");
 
 
int i, n, a[17], b, c, k=0;
long long r;
 
int main()
{
    f>>n;
    a[1]=1;
    for (i=2; i<=15; ++i) a[i]=a[i-1]*5+1;
 
    if (n==0) g<<1;
    else
    {
    while (n>0)
    {
    i=1;
    while (a[i+1]<=n) ++i;
 
    if (n/a[i]%5==0)
        r=-1, n=0;
    else
    {
        r+=n /a[i]*pow(5, i);
        n%=a[i];
    }
 
    }
 
    g<<r;
    }
    return 0;
}