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