#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int x, y, cp = 0, ori = 1;
  scanf("%lld%lld", &x, &y);
  if (y == 0) {
    printf("No\n");
    return 0;
  } else if (y == 1 && x > 0) {
    printf("No\n");
    return 0;
  }
  if (x + 1 >= y) {
    if ((x % 2 != 0 && y % 2 == 0) || (x % 2 == 0 && y % 2 != 0))
      printf("Yes\n");
    else
      printf("No\n");
  } else
    printf("No\n");
  return 0;
  if (y == 0) {
    printf("No\n");
    return 0;
  }
  while (ori < y) {
    ori++;
    cp++;
  }
  while (cp + 2 <= x) {
    cp += 2;
  }
  if (cp == x)
    printf("Yes\n");
  else
    printf("No\n");
}
