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