#include <iostream>
#include <fstream>
using namespace std;

ifstream f("fact.in.txt");
ofstream g("fact.out");

int main()
{
    int p,n=-1,a=0,b=5,aux;
    f>>p;
    if(p==0)
        n=1;
    else
    {
        while(a<p)
        {
            aux=b;
            while((aux%5==0)&&(aux!=0))
            {
                aux=aux/5;
                a++;
            }
            b+=5;
        }
        if(a==p)
           n=b-5;
    }
    g<<n;
}