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