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