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