import re
while True:
    try:
        n = bin(int(input()))[2:]
        lis = []
        for i in range(len(n)):
            for j in range(i,len(n)):
                if re.fullmatch(r'[1]*',n[i:j+1]):
                    lis.append(len(n[i:j+1]))
        print(max(lis))
    except:
        break

用正则表达式的解法