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