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