#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, y;
  int black = 1, white = 0;
  cin >> x >> y;
  if (x == y - 1) {
    cout << "Yes" << endl;
    return 0;
  }
  if (y - x > 1 || y <= 0 || (y == 1 && x > 0)) {
    cout << "No" << endl;
    return 0;
  }
  if ((x - y) % 2 == 1)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
