# import sys # for line in sys.stdin: # a = line.split() # print(int(a[0]) + int(a[1])) n=int(input()) s=input() res=0 max_len=0 last=s[0] if last=='a' or last=='h': res+=1 for i in s[1:]: if i=='a': if last=='h': res+=1 else: res=1 if i=='h': if last=='a': res+=1 else: res=1 last=i max_len=max(max_len,res) max_len=max(max_len,res) print(max_len)