题解 | #挑7#
挑7
https://www.nowcoder.com/practice/ba241b85371c409ea01ac0aa1a8d957b
n =int(input())
countlist = set()
for i in range(1,n+1):
if(i % 7 ==0):
countlist.add(i)
# print(i)
continue
string = str(i)
if("7" in string):
# print(string)
countlist.add(string)
print(len(countlist))
