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 (2.7.6) (judge verdict: Time Limit Exceeded)

# -*- coding: utf-8
import random
Q = 0
L = []
R = []

# http://d.hatena.ne.jp/pashango_p/20090704/1246692091
def is_prime3(q,k=5):
    q = abs(q)
    #計算するまでもなく判定できるものははじく
    if q == 2: return True
    if q < 2 or q&1 == 0: return False

    #n-1=2^s*dとし（但しaは整数、dは奇数)、dを求める
    d = (q-1)>>1
    while d&1 == 0:
        d >>= 1
    
    #判定をk回繰り返す
    for i in xrange(k):
        a = random.randint(1,q-1)
        t = d
        y = pow(a,t,q)
        #[0,s-1]の範囲すべてをチェック
        while t != q-1 and y != 1 and y != q-1: 
            y = pow(y,2,q)
            t <<= 1
        if y != q-1 and t&1 == 0:
            return False
    return True

# 入力部分
Q = int(raw_input())
for i in range(Q):
  l, r = map(int, raw_input().split())
  L.append(l)
  R.append(r)

# 処理部分
for q in range(Q):
  cnt = 0
  for x in range(L[q], R[q]+1):
    if is_prime3(x) & is_prime3((x+1)/2):
      cnt += 1
  print cnt