#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr);
  int x, y;
  cin >> x >> y;
  if (y == 1 && x != 0) cout << "No", exit(0);
  bool ok = false, ok2 = false;
  ok2 = true;
  x -= y - 1;
  if (!(x % 2) && x >= 0 && y > 0) ok = true;
  cout << (ok && ok2 ? "Yes" : "No");
}
