#include<iostream>
#include<fstream>

using namespace std;

int main()
{ ifstream f("fact.in");
  ofstream g("fact.out");
int m,nr,aux,p;
  f>>p;
    m=1;
    nr=0;
    while(nr<p) {
        m=m+5;
        aux=m;
        while(aux%5==0) {aux=aux/5;
            nr++;
        }
    }
    if(nr==m) g<<m;
    else g<<-1;
            return 0;
}