#include <iostream>
#include <fstream>
using namespace std;
long n=0, k=0, p, x;

int main()
{
    ifstream f("factorial.in");
    ofstream g("factorial.out");
    f>>p;
    while(k<p)
    {
        n=n+5;
        x=n;
        while(x!=0 && x%5==0)
        {
            k++;
            x=x/5;
        }
    }
    if(k==p)g<<n; else g<<-1;
    f.close();
    g.close();
    return 0;
}