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