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