#include <bits/stdc++.h>
using namespace std;
int a, b, c, x, y, z, q, w, e;
int main() {
  cin >> a >> b >> c >> x >> y >> z;
  q = a - x;
  if (q > 0) q /= 2;
  w = b - y;
  if (w > 0) w /= 2;
  e = c - z;
  if (e > 0) e /= 2;
  if (q + w + e >= 0)
    cout << "YES";
  else
    cout << "NO";
}
