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