#include <bits/stdc++.h>
using namespace std;
int main() {
  long int x, y, t1, t2, t3;
  cin >> x >> y;
  t1 = y - 1;
  t2 = x - t1;
  if (y == 0) {
    cout << "No";
  } else if (y == 1) {
    if (x == 0)
      cout << "Yes";
    else
      cout << "No";
  } else {
    if (t2 < 0)
      cout << "No";
    else if (t2 % 2 == 0)
      cout << "Yes";
    else
      cout << "No";
  }
  return 0;
}
