#include <bits/stdc++.h>
using namespace std;
template <typename T>
T gcd(T a, T b) {
  return (b == 0) ? a : gcd(b, a % b);
}
template <typename T>
T mod_exp(T b, T p, T m) {
  T x = 1;
  while (p) {
    if (p & 1) x = (x * b) % m;
    b = (b * b) % m;
    p = p >> 1;
  }
  return x;
}
int main() {
  int a[3];
  cin >> a[0] >> a[1] >> a[2];
  int req[3];
  cin >> req[0] >> req[1] >> req[2];
  int diff[3];
  for (int i = 0; i < 3; i++) diff[i] = a[i] - req[i];
  int sum = 0;
  int need = 0;
  for (int i = 0; i < 3; i++) {
    if (diff[i] > 0) sum += diff[i] / 2;
    if (diff[i] < 0) {
      need += (-diff[i]);
    }
  }
  if (sum >= need)
    cout << "Yes\n";
  else
    cout << "No\n";
  return 0;
}
