题解 | 穷哈哈~

import sys

n, s, c, m = int(sys.stdin.readline()), sys.stdin.readline(), 0, 0
for i in range(n):
    if s[i] in ("a", "h"):
        if i > 0 and s[i] != s[i - 1] and s[i - 1] in ("a", "h"):
            c += 1
        else:
            c = 1
    else:
        c = 0
    m = max(c, m)
print(m)