题解 | 穷哈哈~

n = int(input())
s = input()
# ah合法，ha合法，单独的a和h合法
ha_len = 0
curr_len = 0
for i in range(n):
    if s[i] == 'a' or s[i] == 'h':
        if i == 0:
            curr_len += 1
        else:
            if {s[i-1],s[i]} == {'a','h'}:
                curr_len += 1
            else:
                curr_len = 1
    else:
        curr_len = 0
    ha_len = max(curr_len,ha_len)
print(ha_len)