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