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: Wrong Answer)

from sys import stdin
def is_prime(n):
    if n == 1:
        return False
    for i in range(2,int(n**0.5)+1):
        if n % i == 0:
            return False
    return True
prime_list=[i for i in range(2,100000) if is_prime(i)]
oppai=[0]*100000
oppai[1]=0
before=1
for num in prime_list:
    if (num+1)//2 in prime_list:
        oppai[before:num - 2] = [oppai[before]] * (num-1 - before)
        oppai[num-1]=oppai[before]+1
    else:oppai[before:num-1]=[oppai[before]]*(num-before)
    before=num-1
oppai[99992:99999]=[oppai[99991]]*7
N=list(map(int,stdin.readline().strip().split()))[0]
for _ in range(N):
    count = 0
    a,b=list(map(int,stdin.readline().strip().split()))
    if a==b:
        bb = (oppai[b - 1])
        aa = (oppai[a - 2])
        count = bb - aa
        print(count)
    else:
        if a>=2:
            bb = oppai[b - 1]
            aa = oppai[a - 2]
            count = bb - aa
            print(count)
        else:
            bb = oppai[b - 1]
            count = bb
            print(count)