Problem:
Score : 100 points

Problem Statement

In some other world, today is December D-th.

Write a program that prints Christmas if D = 25, Christmas Eve if D = 24, Christmas Eve Eve if D = 23 and Christmas Eve Eve Eve if D = 22.

Constraints

22 \leq D \leq 25

D is an integer.

Input

Input is given from Standard Input in the following format:

D

Output

Print the specified string (case-sensitive).

Sample Input 1

25

Sample Output 1

Christmas

Sample Input 2

22

Sample Output 2

Christmas Eve Eve Eve

Be sure to print spaces between the words.

Solution in OCaml (4.02.3) (judge verdict: Accepted)

open Printf
open Scanf

let (++) = Int64.add
let (--) = Int64.sub
let ( ** ) = Int64.mul
let (//) = Int64.div
let (%%) = Int64.rem
let landl = Int64.logand
let lorl = Int64.logor
let lnotl = Int64.lognot
let lxorl = Int64.logxor
let lsll = Int64.shift_left
let lsrl = Int64.shift_right_logical
let long = Int64.of_int
let succl = Int64.succ
let predl = Int64.pred

let read_int _ = scanf " %d " (fun x -> x)
let read_long _ = scanf " %Ld " (fun x -> x)
let read_str _ = scanf " %s " (fun x -> x)
let read_double _ = scanf " %f " (fun x -> x)

let m = 1_000_000_007L

let rec gcd a b = if b = 0L then a else gcd b (a %% b)

let rec mod_pow a = function
  | 0L -> 1L
  | b -> (if b %% 2L = 0L then 1L else a) ** mod_pow (a ** a %% m) (b//2L) %% m


let () =
  let d = read_int () in
  let c = "Christmas" in
  let e = "Eve" in
  let mes = match d with
    | 22 -> sprintf "%s %s %s %s" c e e e
    | 23 -> sprintf "%s %s %s" c e e
    | 24 -> sprintf "%s %s" c e
    | 25 -> c
    | _ -> assert false
  in
  printf "%s\n" mes