题解 | #挑7#

'''
解题思路：
含7数字i的条件为：i%7==0 or '7' in str(i)
'''

while 1:
    try:
        pass

        n = int(input())

        S = []
        for i in range(1,n+1):
            #print(i)
            if i%7==0 or '7' in str(i):
                S.append(i)
                #print(i)
        print(len(S))  

    except:
        break