#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
const int inf = INT_MAX;
const int lim = 1e5 + 5;
long long power(long long a, long long b) {
  long long ret = 1;
  while (b) {
    if (b & 1) ret *= a;
    a *= a;
    if (ret >= mod) ret %= mod;
    if (a >= mod) a %= mod;
    b >>= 1;
  }
  return ret;
}
long long inv(long long x) { return power(x, mod - 2); }
int main() {
  int x, y;
  cin >> x >> y;
  if (y == 0 || x < y - 1) {
    cout << "No\n";
    return 0;
  }
  if (y == 1) {
    if (x == 0)
      cout << "Yes\n";
    else
      cout << "No\n";
    return 0;
  }
  y -= 1;
  int temp = x - y;
  if (temp & 1) {
    cout << "No\n";
    return 0;
  }
  cout << "Yes\n";
}
