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

int main(){
  int p, aux, i;
  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;
  */

  for(i = 5; i <= p; i += 5)
  {
    aux = i;
    while(!(aux%5))
    {
      p--;
      aux /= 5;
    }
  }

  if(p < i-5)
    out << -1;
  else
    out << p*5;

  return 0;
}