题解 | #挑7#

# -*-coding:utf-8-*-
while True:
        try:
            n = int(input())
            k = []
            for i in range(1 , n + 1):
                if i % 7 == 0:
                    k.append(i)
                elif '7' in str(i):
                    k.append(i)
                else:continue
            print(len(k))
        except:
            break