#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y;
  cin >> x >> y;
  long long copy = 0, orig = 0;
  orig = y - 1;
  x -= orig;
  if (x < 0)
    cout << "No";
  else if (y == 0)
    cout << "No";
  else if (x > 0 && y == 1)
    cout << "No";
  else if (x % 2 == 0) {
    cout << "Yes";
  } else
    cout << "No";
}
