Buggy python submission (verdict: Runtime Error):
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])



Fixed submission:
import sys
sys.setrecursionlimit(500000)
 
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])

Buggy python submission (verdict: Runtime Error):
N = int(input())
graph = [[] for _ in range(N+1)] #木構造を入れておく
long = [0] * (N+1) #Kから任意のノードまでの距離

for i in range(N-1):
  x, y, z = map(int, input().split())
  graph[x].append([y, z])
  graph[y].append([x, z])
  
Q, K = map(int, input().split())
def dfs(n, num):
    for t in graph[n]:
        if t[0] == num:
            continue
        else:
            long[t[0]] = long[n] + t[1]
            dfs(t[0], n)
 
 
dfs(K, 0)

for i in range(Q):
  x_i, y_i = map(int, input().split())
  ans = long[x_i] + long[y_i]
  print(ans)

Fixed submission:
import sys
sys.setrecursionlimit(500000)
 
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])

Buggy python submission (verdict: Runtime Error):
N = int(input())
graph = [[] for _ in range(N+1)] #木構造を入れておく
long = [0] * (N+1) #Kから任意のノードまでの距離

for i in range(N-1):
  x, y, z = map(int, input().split())
  graph[x].append([y, z])
  graph[y].append([x, z])
  
Q, K = map(int, input().split())
x = list()
y = list()

for i in range(Q):
  x_i, y_i = map(int, input().split())
  x.append(x_i)
  y.append(y_i)

       
def dfs(n, np):
    for nc in graph[n]:
        if nc[0] == np:
            continue
        else:
            long[nc[0]] = long[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)

for i in range(Q):
  ans = long[x[i]] + long[y[i]]
  print(ans)

Fixed submission:
import sys
sys.setrecursionlimit(500000)
 
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

N = int(input())
graph = [[] for _ in range(N+1)] #木構造を入れておく
long = [0] * (N+1) #Kから任意のノードまでの距離

for i in range(N-1):
  x, y, z = map(int, input().split())
  graph[x].append([y, z])
  graph[y].append([x, z])
  
Q, K = map(int, input().split())
x = [0] * Q
y = [0] * Q

for i in range(Q):
  x_i, y_i = map(int, input().split())
  x[i] = x_i
  y[i] = y_i
  
for i in range(1,N+1): #Kから任意のノードまでの距離を求める
  q = deque([K])
  while q:
    t = q.popleft()
    tlen = len(graph[t])
    for i in range(tlen):
      next_t = graph[t][i][0]
      if(long[next_t] > 0):
        continue
      q.append(next_t)
      long[next_t] = long[t] + graph[t][i][1]
        

for i in range(Q):
  print(long[x[i]] + long[y[i]])

Fixed submission:
import sys
sys.setrecursionlimit(500000)
 
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

N = int(input())
graph = [[] for _ in range(N+1)] #木構造を入れておく
long = [0] * (N+1) #Kから任意のノードまでの距離

for i in range(N-1):
  x, y, z = map(int, input().split())
  graph[x].append([y, z])
  graph[y].append([x, z])
  
Q, K = map(int, input().split())
x = list()
y = list()

for i in range(Q):
  x_i, y_i = map(int, input().split())
  x.append(x_i)
  y.append(y_i)

  
for i in range(1,N+1): #Kから任意のノードまでの距離を求める
  q = deque([K])
  while q:
    t = q.popleft()
    for i in range(len(graph[t])):
      next_t = graph[t][i][0]
      if(long[next_t] > 0):
        continue
        
      else:
        q.append(next_t)
        long[next_t] = long[t] + graph[t][i][1]
        

for i in range(Q):
  ans = long[x[i]] + long[y[i]]
  print(ans)


Fixed submission:
import sys
sys.setrecursionlimit(500000)
 
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque

N = int(input())
graph = [[] for _ in range(N+1)] #木構造を入れておく
long = [0] * (N+1) #Kから任意のノードまでの距離

for i in range(N-1):
  x, y, z = map(int, input().split())
  graph[x].append([y, z])
  graph[y].append([x, z])
  
Q, K = map(int, input().split())
x = list()
y = list()

for i in range(Q):
  x_i, y_i = map(int, input().split())
  x.append(x_i)
  y.append(y_i)

  
for i in range(1,N+1): #Kから任意のノードまでの距離を求める
  q = deque([K])
  while q:
    t = q.popleft()
    for i in range(len(graph[t])):
      next_t = graph[t][i][0]
      if(long[next_t] > 0):
        continue
        
      else:
        q.append(next_t)
        long[next_t] = long[t] + graph[t][i][1]
        

for i in range(Q):
  ans = long[x[i]] + long[y[i]]
  print(ans)

Fixed submission:
import sys
sys.setrecursionlimit(500000)
 
N = int(input())
ABC = [list(map(int, input().split())) for i in range(N-1)]
Q, K = map(int, input().split())
D = [0] * (N+1)
L = [[] for i in range(N+1)]
for a, b, c in ABC:
    L[a].append([b, c])
    L[b].append([a, c])
 
 
def dfs(n, np):
    for nc in L[n]:
        if nc[0] == np:
            continue
        else:
            D[nc[0]] = D[n] + nc[1]
            dfs(nc[0], n)
 
 
dfs(K, 0)
for i in range(Q):
    x, y = map(int, input().split())
    print(D[x] + D[y])