题解 | #穷哈哈~#

简单的状态转移

n=int(input())
s=input()
dp=[0]*n
for i in range(0,n):
    if(i>0 and s[i-1]=='a' and s[i]=='h'):
        dp[i]=dp[i-1]+1
    elif(i>0 and s[i-1]=='h' and s[i]=='a'):
        dp[i]=dp[i-1]+1
    elif(s[i]=='a' or s[i]=='h'):
        dp[i]=1
print(max(dp))