#include <bits/stdc++.h>
using namespace std;
const int M = 1e6 + 7;
int main() {
  int n, m;
  cin >> n >> m;
  if (m == 0) {
    cout << "No" << endl;
    return 0;
  }
  if (m == 1 && n != 0) {
    cout << "No" << endl;
    return 0;
  }
  if (n + 1 < m) {
    cout << "No" << endl;
    return 0;
  }
  if ((n & 1) ^ (m & 1)) {
    cout << "Yes" << endl;
    return 0;
  } else
    cout << "No" << endl;
  return 0;
}
