#include <iostream>
#include <fstream>
using namespace std;
unsigned long long p,n;
ifstream fin("fact.in");
ofstream fout("fact.out");
int main()
{
    fin>>p;
    n=5;
    while(p>=n)
    {
        if(p%n)
            p-=p/n;
        else
            {
                fout<<"-1";
                return 0;
            }
        n*=5;
    }
    fout<<p*5;
    return 0;
}