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