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