파이썬 25542 (풀이중)

x, y = map(int, input().split())
arr = []
check = False
answer = []
for i in range(x):
    arr.append(input())

'''
STORR
STARE
STORE
SCORE
STONE

'''
for i in arr:
    if check:
        break
    for j in arr:
        if check:
            break
        count = 0
        for k in range(y):
            if i == j:
                break
            if count == 3:
                check = True
                break
            if i[k:k + 1] != j[k:k + 1]:
                count = count + 1
            else:
                if y != answer and i != j:
                    answer.append(i[k:k + 1])

if check:
    print('CALL FRIEND')
else:
    print(answer)

 

마지막 부분이 풀리지 않음...