const input = require('fs').readFileSync('/dev/stdin', 'utf8');

const list = input.split(' ');

const n = Number(list[0]);

const k = Number(list[1]);

const isEven = (t) => {
  if(t % 2 === 0) {
    return true;
  } else {
    return false;
  }
};

const output = () => {
  if (isEven(n)) {
    if (n / 2 < k) {
      console.log('NO');
    } else {
      console.log('YES')
    }
  } else {
    if ((n + 1) / 2 < k) {
      console.log('NO');
    } else {
      console.log('YES');
    }
  }
};

output();
