题解 | #挑7#

while True:
    try:
        n = int(input())
        res = []
        for i in range(6,n+1):
            if i%7 == 0:
                res.append(i)
            else:
                for j in range(len(str(i))):
                    if str(i)[j] == '7' and i not in res:
                        res.append(i)
        print(len(res))
    except:
        break