#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int a[3], b[3], c = 0, p = 0;
  for (int i = 0; i < 3; i++) cin >> a[i];
  for (int i = 0; i < 3; i++) cin >> b[i];
  for (int i = 0; i < 3; i++) {
    if (a[i] > b[i])
      c += (a[i] - b[i]) / 2;
    else
      p += b[i] - a[i];
  }
  if (c >= p)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
