백준 1316 그룹 단어 체커

https://www.acmicpc.net/problem/1316

1316번: 그룹 단어 체커

n = int(input())
result = 0
for _ in range(n):
    inp = input()
    alpha = [inp[0]]
    s = inp[0]
    b = 0
    for i in range(1, len(inp)):
        if inp[i] == s:
            continue
        else:
            if inp[i] not in alpha:
                alpha.append(inp[i])
                s = inp[i]
            else:
                b = 1
                break
    if b == 0:
        result += 1
print(result)