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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {

static boolean pd(int num){
if(num==1)return false;
if(num==2||num==3) return true;
if(num%6!=1&&num%6!=5) return false;
 int tmp=(int) Math.sqrt(num); 
for(int i=5;i<tmp;i+=6)
	if(num%i==0||num%(i+2)==0)
  return false;
return true;}
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
int n=in.nextInt();
for(int i = 0;i<n;i++){
int a,b,ans=0;
a=in.nextInt();
b=in.nextInt();
if(a%2==0){
	for(int j=a+1;j<=b;j+=2){
		if(pd(j)&&pd((j+1)/2)){
			ans++;
		}	
		}
}
else{
for(int j=a;j<=b;j+=2){
if(pd(j)&&pd((j+1)/2)){
	ans++;
}	
}}
System.out.println(ans);
ans=0;
}
}
}