#include <bits/stdc++.h>
using namespace std;
int n, m, k, i, o, ans, p, l;
int main() {
  cin >> n >> m;
  if (m == 0) {
    cout << "No";
    return 0;
  }
  if (m == 1 && n == 0) {
    cout << "Yes";
    return 0;
  }
  if (m == 1) {
    cout << "No";
    return 0;
  }
  if (n - m + 1 >= 0 && (n - m + 1) % 2 == 0)
    cout << "Yes";
  else
    cout << "No";
}
