Problem:
Score : 400 points

Problem Statement

We say that a odd number N is similar to 2017 when both N and (N+1)/2 are prime.

You are given Q queries.

In the i-th query, given two odd numbers l_i and r_i, find the number of odd numbers x similar to 2017 such that l_i ≤ x ≤ r_i.

Constraints

1≤Q≤10^5

1≤l_i≤r_i≤10^5

l_i and r_i are odd.

All input values are integers.

Input

Input is given from Standard Input in the following format:

Q
l_1 r_1
:
l_Q r_Q

Output

Print Q lines. The i-th line (1≤i≤Q) should contain the response to the i-th query.

Sample Input 1

1
3 7

Sample Output 1

2

3 is similar to 2017, since both 3 and (3+1)/2=2 are prime.

5 is similar to 2017, since both 5 and (5+1)/2=3 are prime.

7 is not similar to 2017, since (7+1)/2=4 is not prime, although 7 is prime.

Thus, the response to the first query should be 2.

Sample Input 2

4
13 13
7 11
7 11
2017 2017

Sample Output 2

1
0
0
1

Note that 2017 is also similar to 2017.

Sample Input 3

6
1 53
13 91
37 55
19 51
73 91
13 49

Sample Output 3

4
4
1
1
1
2

Solution in Python (3.4.3) (judge verdict: Time Limit Exceeded)

import math

def is_prime(x):
    if x < 2: return False
    if x == 2 or x == 3 or x == 5: return True
    if x % 2 == 0 or x % 3 == 0 or x % 5 == 0: return False

    prime = 7
    step = 4
    while prime <= math.sqrt(x):
        if x % prime == 0: return False

        prime += step
        step = 6 - step

    return True

def my_chk(num):
    if is_prime(num):
        if is_prime((num+1)*0.5):
            return 1
        else:
            return 0
    else:
        return 0
    
if __name__ == '__main__':
    q = int(input())
    ans = []
    for i in range(q):
        info = list(map(int,input().split(" ")))
        chk_list = [ele for ele in range(info[0],info[1]+1,2)]
        temp = list(map(my_chk,chk_list))
        ans.append(sum(temp))
    for ele in ans:
        print(ele)