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