题解 | #挑7#

# 先求7的倍数，再求包含7的个数
while True:
    try:
        n = int(input())
        arr = []
        for i in range(1, n + 1):
            if i % 7 == 0:
                arr.append(i)
            elif '7' in str(i):
                arr.append(i)
            else:
                continue
        print(len(arr))
    except:
        break