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 (3.8.2) (judge verdict: Accepted)

q=int(input())
lr=[tuple(map(int,input().split())) for _ in range(q)]

def main():
  n=10**5
  ansl=[]
  sieve=[1]*(n+1)
  sieve[0],sieve[1]=0,0
  for i in range(2,n):
    if sieve[i]:
      sieve[2*i::i]=[0 for _ in range(2*i,n+1,i)]
  ans=[0]*(n+1)
  for i in range(3,n):
    if sieve[i]==1 and sieve[(i+1)//2]==1:
      ans[i]=ans[i-1]+1
    else:
      ans[i]=ans[i-1]

  for e in lr:
    print(ans[e[1]]-ans[e[0]-1])

if __name__=='__main__':
  main()