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