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