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: Accepted)

import sys
from itertools import accumulate

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10 ** 9)
INF = 1 << 60


def prime_numbers(n):
    if n < 2:
        return []

    m = (n + 1) // 2
    p = [1] * m
    for i in range(1, int((n ** 0.5 - 1) / 2) + 1):
        if p[i]:
            p[2 * i * (i + 1) :: 2 * i + 1] = [0] * (((m - 1) - 2 * i * (i + 1)) // (2 * i + 1) + 1)

    return {2} | {2 * i + 1 for i in range(1, m) if p[i]}


def main():
    primes = prime_numbers(10 ** 5)
    A = [n % 2 and n in primes and (n + 1) // 2 in primes for n in range(10 ** 5 + 1)]
    A = tuple(accumulate(A))

    Q, *LR = map(int, open(0).read().split())
    ans = []
    for l, r in zip(LR[::2], LR[1::2]):
        ans.append(A[r] - A[l - 1])

    print(*ans, sep='\n')
    return


if __name__ == '__main__':
    main()