#include <bits/stdc++.h>
using namespace std;
long long temp;
void solve(int k) {
  if (k > 0) {
    temp += k / 2;
  } else
    temp += k;
}
int main() {
  long a1, a2, a3;
  long b1, b2, b3;
  cin >> a1 >> a2 >> a3;
  cin >> b1 >> b2 >> b3;
  a1 -= b1;
  a2 -= b2;
  a3 -= b3;
  solve(a1);
  solve(a2);
  solve(a3);
  if (temp >= 0)
    cout << "YES";
  else
    cout << "NO";
}
