题解 | #挑7#

import sys

while True:
    try:
        a=input()
        s= int(a)
        cnt=0
        for i in range(1,s+1):
            if '7' in str(i):
                cnt+=1
            else:
                if i%7==0:
                    cnt+=1
        print(cnt)
            
    except:
        break