#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  int x, y;
  cin >> y >> x;
  if (x < 1) {
    cout << "No\n";
  } else if (x == 1) {
    if (y == 0) {
      cout << "Yes\n";
    } else {
      cout << "No\n";
    }
  } else {
    int copies = x - 1;
    if (copies > y) {
      cout << "No\n";
    } else {
      int left_copies = y - copies;
      if (left_copies % 2 == 0) {
        cout << "Yes\n";
      } else {
        cout << "No\n";
      }
    }
  }
  return 0;
}
