#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, y;
  scanf("%d%d", &x, &y);
  int a = 0, b = 1, pd = 0;
  if (y == 0)
    printf("No");
  else if (x == 0 && y == 1)
    printf("Yes");
  else if (x != 0 && y == 1)
    printf("No");
  else {
    a = y - 1;
    if ((x - a) % 2 == 0 && (x - a) >= 0 && a >= 0)
      printf("Yes");
    else
      printf("No");
  }
  return 0;
}
