n,k = map(int, input().split())

a = list(map(int, input().split()))
c = list(map(int, input().split()))

ans = 0
for i in range(n):
  aa = a[i:] + a[:i]
  cc = c[i:] + c[:i]
  
  ok = [cc[0]]
  now = aa[0]
  for j in range(1, n):
    ok2 = []
    for v in ok:
      if(cc[j]-k <= v and v <= cc[j]+k):
        ok2.append(v)
        
    
    
    if(len(ok2)==0):
      break
    ok.append(cc[j])
    now+=aa[j]
    #print(i,j,ok2, now)
    #ok = ok2
    
  ans = max(ans, now)
  #print(i, ans)
  
print(ans)