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