소프티어

아래 경우에 오답 케이스를 알 수 있을까요?

어느 부분이 잘못됐는지 못찾겠네요..

import sys
from collections import deque

n, m = map(int, input().split())
adj = [[] for _ in range(n + 1)]
adj_reverse = [[] for _ in range(n + 1)]
for _ in range(m) :
    a, b = map(int, input().split())
    adj[a].append(b)
    adj_reverse[b].append(a)
S, T = map(int, input().split())

visited_1 = [0] * (n + 1)
visited_1_R = [0] * (n + 1)
visited_2 = [0] * (n + 1)
visited_2_R = [0] * (n + 1)

def BFS(start, end, visited) :
    queue = deque()
    queue.append(start)
    visited[start] = 1
    
    while queue :
        now = queue.popleft()
        if now == end :
            continue
        for neighbor in adj[now] :
            if not visited[neighbor] :
                visited[neighbor] = 1
                queue.append(neighbor)

BFS(S, T, visited_1)
BFS(S, T, visited_1_R)
BFS(T, S, visited_2)
BFS(T, S, visited_2_R)
visited_1[S] = visited_1[T] = 0
visited_1_R[S] = visited_1_R[T] = 0
visited_2[S] = visited_2[T] = 0
visited_2_R[S] = visited_2_R[T] = 0

cnt = 0
for i in range(1, n + 1) :
    if visited_1[i] and visited_1_R[i] and visited_2[i] and visited_2_R[i] :
        cnt += 1
print(cnt)