"use strict";
function I(s,f){this._s=s;this._c=0;this._l=0;this._f=f||Number}I.prototype.a=function(){var l=this._s.split("\n")[this._l];if(!l)return;var t=l.trim().split(" ");var a=t[this._c];this._c++;if(t.length===this._c){this._c=0;this._l++}return this._f(a)};I.prototype.l=function(){var l=this._s.split("\n")[this._l];this._c=0;this._l++;return l.split(" ").map(this._f)};

// TODO test and remove comment
function main(input) {
  const o = new I(input);

  const N = o.a();
  const K = o.a();

  console.log(N + 1 >= 2 * K ? "YES" : "NO")
}


main(require("fs").readFileSync("/dev/stdin", "utf8"));
