#include <iostream>
#include <fstream>

using namespace std;

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

const int L = 28;

int n, k, p;

int nr_zero (int n)
{
    int nr=0;
    while (n>0)
    {
        nr += (n/=5);
    }
    return nr;
}

int main()
{
    in >> p;
    int r=0, pas=1<<L;
    while (pas!=0)
    {
        if (nr_zero(r+pas)<p)
        {
            r+=pas;
        }
        pas/=2;
    }
    r++;
    if (nr_zero(r) != p)
    {
        r = -1;
    }
    out << r;
    return 0;
}