#include <fstream>
#include <iostream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");

int main(){
  int p, n = 0, aux;
  in >> p;
  if(!p){
    out << -1;
    return 0;
  }

  while(p > 0){
    n += 5;
    aux = n;
    while(!(aux % 5)){
      aux /= 5;
      p--;
    }
  }
  if(!p) out << n;
  else out << -1;

  return 0;
}