Double Happiness

题意翻译

**题目描述** 给定闭区间$ [l,r] $,找出区间内满足$ t=a^{2}+b^{2} $的所有素数$ t $的个数( $ a,b $为任意正整数). **输入格式** 输入只有一行 给定两个正整数$ l,r $表示区间范围 **输出格式** 输出一个数字 表示共有多少个素数t

题目描述

On the math lesson a teacher asked each pupil to come up with his own lucky numbers. As a fan of number theory Peter chose prime numbers. Bob was more original. He said that number $ t $ is his lucky number, if it can be represented as: $ t=a^{2}+b^{2}, $ where $ a,b $ are arbitrary positive integers.Now, the boys decided to find out how many days of the interval $ [l,r] $ ( $ l<=r $ ) are suitable for pair programming. They decided that the day $ i $ ( $ l<=i<=r $ ) is suitable for pair programming if and only if the number $ i $ is lucky for Peter and lucky for Bob at the same time. Help the boys to find the number of such days.

输入输出格式

输入格式


The first line of the input contains integer numbers $ l,r $ ( $ 1<=l,r<=3·10^{8} $ ).

输出格式


In the only line print the number of days on the segment $ [l,r] $ , which are lucky for Peter and Bob at the same time.

输入输出样例

输入样例 #1

3 5

输出样例 #1

1

输入样例 #2

6 66

输出样例 #2

7