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 bisect

# ある自然数未満までのエラトステネスの篩をつくる
def mark(s, x):
    for i in range(x + x, len(s), x):
        s[i] = False


def eratosthenes(n):
    s = [True] * n
    for x in range(2, int(n ** 0.5) + 1):
        if s[x]: mark(s, x)
    return [i for i in range(0, n) if s[i] and i > 1]


primes = eratosthenes(10 ** 5+1)
like2017 = list(filter(lambda x: (x+1)/2 in primes, primes))
num_like2017 = len(like2017)

Q = int(input())
for i in range(Q):
    l, r = map(int, input().split())
    left = bisect.bisect_left(like2017, l)
    right = num_like2017 - bisect.bisect_right(like2017, r)

    print(num_like2017 - left - right)