#include <bits/stdc++.h>
const long long int oo = 9e18;
using namespace std;
int x, y, o, c;
int main(void) {
  scanf("%d%d", &x, &y);
  if (x < y - 1 || (x == 0 && y > 1) || y == 0 || (y == 1 && x != 0)) {
    puts("No");
    exit(0);
  }
  if ((x - (y - 1)) % 2 == 0)
    puts("Yes");
  else
    puts("No");
  return 0;
}
