题解 | #挑7#

n = int(input())
count = 0
for i in range(n):
    num = i + 1
    divisible = num % 7
    include_seven = False
    for j in range(len(str(num))):
        if str(num)[j] == '7':
            include_seven = True
    if divisible == 0 or include_seven:
        count += 1
print(count)