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