#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, m;
  cin >> m >> n;
  if ((m - n) % 2 == 0 || n - 1 > m || n == 0) {
    cout << "No";
  } else {
    if (n == 1 && m > 0) {
      cout << "No";
    } else {
      cout << "Yes";
    }
  }
}
