#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;
main()
{
    ifstream f1("fact.in");
    ofstream f2("fact.out");
    long int n=0, p, pow5=0, k;
    f1>>p;
    n = 5 * p;
    while (n >= 0)
    {
        k = n;
        while (k % 5 == 0){
            k = k / 5;
            pow5++;
        }
        n = n - 5;
    }
    if (pow5 == p) f2 << 5 * p;
    else f2 << -1;
}