#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, i, j, x, y;
  cin >> x >> y;
  if (x == 0 && y == 1) {
    cout << "Yes";
    return 0;
  }
  y--;
  if (y <= 0)
    cout << "No";
  else {
    if (x < y)
      cout << "No";
    else {
      if ((x - y) % 2)
        cout << "No";
      else
        cout << "Yes";
    }
  }
  return 0;
}
