Time Limit: 2 sec / Memory Limit: 976 MB
配点: 200 点
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
- N は 1 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.