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