题解 | #挑7#

while True:
    try:
        i = 1
        num = int(input())
        count = 0
        a = []
        for i in range(1,num + 1):
            if(i % 7 == 0): #如果是7的倍数则直接count+1
                count += 1
                continue
            a.append(str(i)) #否则放到a中
        for i in a: #判断a中的每个数哪个包含7
            b = list(i)
            if '7' in b:
                count += 1
        print(count)
    except:
        break