#include <fstream>
#include <cmath>
#include <algorithm>
using namespace std;

ifstream cin("fact.in");
ofstream cout("fact.out");


int i, n, a[15], b, c, k=0;
long long r;

int main()
{
    cin>>n;
    a[1]=1;
    for (i=2; i<=13; ++i) a[i]=a[i-1]*5+1;


    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];
    }

    }

    cout<<r;

    return 0;
}