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 PyPy3 (2.4.0) (judge verdict: Wrong Answer)

import math
import itertools
import bisect
import sys
input = sys.stdin.readline


# 素数判定
def eratosthenes(limit):
    A = [i for i in range(2, limit+1)]
    P = []
    time = 0

    while True:
        prime = min(A)

        if prime > math.sqrt(limit):
            break

        P.append(prime)

        i = 0
        while i < len(A):
            if A[i] % prime == 0:
                A.pop(i)
                continue
            i += 1
    for a in A:
        P.append(a)

    return P

q=int(input())
s= [list(map(int, input().split())) for i in range(q)]
v=eratosthenes(100)
ans=[]
for i in range(len(v)):
    x=(v[i]+1)//2
    index = bisect.bisect_left(v, x)
    if v[index]==x:
        ans.append(v[i])

for i,j in s:
    r = bisect.bisect_left(ans, j+1)
    l = bisect.bisect_left(ans, i-1)
    print(r-l)