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