//a로 부터 root까지의 거리
def distR(a):
n = 1
while parent[a] != 1:
a = parent[a]
n += 1
return n
//a와 b의 공통조상 발견
def findP(a,b,a_d,b_d):
if a_d > b_d:
while a_d != b_d:
a = parent[a]
a_d -= 1
else:
while a_d != b_d:
b = parent[b]
b_d -= 1
if a_d == b_d:
while parent[a] != parent[b]:
a = parent[a]
b = parent[b]
return parent[a]
//공통조상의 모든 자손의 수
def findC(parent):
m = 1
for i in range(len(child[parent])):
m += findC(child[parent][i])
return m
for t in range(int(input())):
v,e,a,b = map(int,input().split())
lis = list(map(int,input().split()))
child = [[]for _ in range(v+2)]
parent = [0]*(v+2)
for i in range(0,e*2,2):
parent[lis[i+1]] = lis[i]
child[lis[i]].append(lis[i+1])
a_d = distR(a)
b_d = distR(b)
prt = findP(a,b,a_d,b_d)
cld = findC(prt)
print(f'#{t+1} {prt} {cld}')
