Double Happiness

3000ms

131072K

Description:

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 = a² + b², 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.

Input:

The first line of the input contains integer numbers l, r (1 ≤ l, r ≤ 3·10⁸).

Output:

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.

Sample Input:

3 5

Sample Output:

Sample Input:

6 66

Sample Output:

Informação

Provedor Codeforces

Código CF113C