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)

def is_prime(q):
    q = abs(q)
    if q == 2: return True
    if q < 2 or q & 1 == 0: return False
    return pow(2, q - 1, q) == 1


def main():
    Q = int(input())
    dp = [-1 for _ in range(1000000)]
    for _ in range(Q):
        cnt = 0
        l, r = map(int, input().split())
        for x in range(l, r + 1):
            if dp[x] != -1:
                if dp[x] == 1:
                    cnt += 1
                    continue

            if is_prime(x) and is_prime((x+1)//2):
                dp[x] = 1
                cnt += 1
            else:
                dp[x] = 0

        print(cnt)

main()