#include <bits/stdc++.h>
using namespace std;
int a, b, c, x, y, z, s[3], needed, r;
int main(int args, char** argv) {
  scanf("%d%d%d%d%d%d", &a, &b, &c, &x, &y, &z);
  s[0] = a - x;
  s[1] = b - y;
  s[2] = c - z;
  sort(s, s + 3);
  for (int i = 0; i < 3; i++)
    if (s[i] < 0)
      needed += abs(s[i]);
    else
      r += s[i] / 2;
  if (r - needed >= 0)
    printf("YES");
  else
    printf("NO");
  return 0;
}
