#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int x, y;
  scanf("%d%d", &x, &y);
  int a = 0, b = 1;
  if (y == 0) {
    puts("No");
    return 0;
  }
  while (b != y) {
    a++;
    b++;
  }
  if (a != 0) {
    while (a < x) {
      a += 2;
    }
  }
  printf("%s\n", a == x ? "Yes" : "No");
  return 0;
}
