Laskettelukeskus

n = int(input())
graph = [[]for i in range(n+1)]
up = [[]for i in range(n+1)]
leafs = []
for i in range(n-1):
  j, r  = map(int,input().split())
  if j not in leafs and j!=1:
      leafs.append(j)
  elif r not in leafs and r!=1:
      leafs.append(r)
  graph[j].append(r)
  up[r].append(j)
l = list(map(int,input().split()))
l1=l[0]
l2=l[1]
l[0]=0
def go_up(leaf):
    if leaf>0:
        st = leaf
        while True:
            st = up[st][0]
            if st != 1:
                l[st-1]-=l[leaf-1]
            else:
                break
        l[0]-=l[leaf-1]
        l[leaf-1]=0

if len(l)==2:
    print(max(l1,l2))
else:
    i=0
    while len(leafs)!=0:
        leaf = leafs[i]
        if l[leaf-1]>0 and len(graph[leaf]) == 0:
            go_up(leaf)
            if up[leaf][0] not in leafs and up[leaf][0]!=1:
                leafs.append(up[leaf][0])
            graph[up[leaf][0]].remove(leaf)
        leafs.remove(leaf)
        i=0
    print(max(abs(l[0]),l1))

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: WRONG ANSWER

Test 3

Group: 1, 2

Verdict: WRONG ANSWER

Test 4

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 5

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 1, 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 1, 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 1, 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: TIME LIMIT EXCEEDED