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