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