#include <bits/stdc++.h>
using namespace std;
const int MAX = 0xfffffff;
const int N = 100000;
int x, y, z;
int a, b, c;
int main() {
  scanf("%d %d %d", &x, &y, &z);
  scanf("%d %d %d", &a, &b, &c);
  int sum = 0;
  int s1 = x - a;
  int s2 = y - b;
  int s3 = z - c;
  sum += s1 > 0 ? s1 / 2 : s1;
  sum += s2 > 0 ? s2 / 2 : s2;
  sum += s3 > 0 ? s3 / 2 : s3;
  printf("%s\n", sum >= 0 ? "YES" : "NO");
  return 0;
}
