#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  int a, b;
  cin >> b >> a;
  if (a < 1) {
    cout << "No" << endl;
  } else if (a == 1) {
    if (b) {
      cout << "No" << endl;
    } else {
      cout << "Yes" << endl;
    }
  } else {
    int curb = (a - 1);
    if (b < curb) {
      cout << "No" << endl;
      return 0;
    }
    if ((curb & 1) == (b & 1)) {
      cout << "Yes" << endl;
    } else {
      cout << "No" << endl;
    }
  }
  return 0;
}
