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