#include <bits/stdc++.h>
using namespace std;
const long long maxn = 3e5 + 123, N = 1e3, inf = 1e9, mod = 1e9 + 7;
long long x, y, k, ans;
int main() {
  ios_base::sync_with_stdio(false);
  cin >> x >> y;
  if (y == 1 && x > 0) {
    cout << "NO";
    return 0;
  }
  if (y != 0 && (x + y) % 2 == 1 && x >= y - 1 && (y - (x - 1)) % 2 == 0)
    cout << "Yes";
  else
    cout << "No";
}
