题解 | 穷哈哈~

N = int(input())
S = input()

maxL = curL = 0
for i in range(N):
    if S[i] in ("a", "h"):  # 符合要求
        if i == 0:
            curL = 1
        elif S[i] != S[i - 1] and S[i - 1] in ("a", "h"):
            curL += 1
        else:  # 序列中断
            curL = 1
    else:  # 不符合要求
        curL = 0
    maxL = max(maxL, curL)
print(maxL)