#include <bits/stdc++.h>
const long long LINF = 1e18;
const int INF = 1e9;
const int M = 1e9 + 7;
const double EPS = 1e-9;
using namespace std;
int main() {
  std::ios_base::sync_with_stdio(0);
  long long x, y;
  cin >> x >> y;
  if (y == 0 || (y == 1 && x > 0)) {
    cout << "No";
    return 0;
  }
  long long curx = y - 1, cury = y;
  if (curx % 2 == x % 2 && x >= curx)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
