function Main(input) {
  input = input.trim()
  var ans = "Christmas"
  switch(input){
    case "22":
      ans += " Eve"
    case "23":
      ans += " Eve"
    case "24":
      ans += " Eve"
    default:
      break;
              }
  console.log(ans)
}Main(require("fs").readFileSync("/dev/stdin", "utf8"));
