#include <bits/stdc++.h>
int main() {
  int x[3], y[3], z[3];
  int m, sum1, sum2, sum3;
  m = sum1 = sum2 = sum3 = 0;
  scanf("%d%d%d", &x[0], &x[1], &x[2]);
  scanf("%d%d%d", &y[0], &y[1], &y[2]);
  for (int i = 0; i < 3; i++) {
    z[i] = x[i] > y[i] ? (x[i] + 1 - y[i]) / 2 : 0;
    sum1 += x[i];
    sum2 += y[i];
    int t = x[i] - 2 * z[i];
    sum3 += t > 0 ? t : 0;
    m += z[i];
  }
  if (sum2 - m + m * 2 > sum1)
    printf("no\n");
  else if (sum2 - m + m * 2 == sum1)
    printf("yes\n");
  else {
    if (sum3 > m + sum2)
      printf("no\n");
    else
      printf("yes\n");
  }
  return 0;
}
