B - 105 Editorial /

Time Limit: 2 sec / Memory Limit: 976 MB

配点: 200

問題文

105 という数は, 非常に特殊な性質を持つ - 奇数なのに, 約数が 8 個もある.
さて, 1 以上 N 以下の奇数のうち, 正の約数を ちょうど 8 個持つようなものの個数を求めよ.

制約

  • N1 以上 200 以下の整数

入力

入力は以下の形式で標準入力から与えられる.

N

出力

条件を満たす数の個数を出力しなさい.


入力例 1

105

出力例 1

1

1 以上 105 以下の整数の中で, ただ一つの「奇数かつ約数が 8 個」を満たす数は 105 である.


入力例 2

7

出力例 2

0

1 は約数が 1 個, 3, 5, 7 は全て素数なので約数が 2 個である. よって前述の条件を満たすような数は存在しない.

Score: 200 points

Problem Statement

The number 105 is quite special - it is odd but still it has eight divisors. Now, your task is this: how many odd numbers with exactly eight positive divisors are there between 1 and N (inclusive)?

Constraints

  • N is an integer between 1 and 200 (inclusive).

Input

Input is given from Standard Input in the following format:

N

Output

Print the count.


Sample Input 1

105

Sample Output 1

1

Among the numbers between 1 and 105, the only number that is odd and has exactly eight divisors is 105.


Sample Input 2

7

Sample Output 2

0

1 has one divisor. 3, 5 and 7 are all prime and have two divisors. Thus, there is no number that satisfies the condition.