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