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