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 C (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>


int p[8]={4,2,4,2,4,6,2,6};
int prime(int n)
{
    int i=7,j,q;
    if(n==1)return 0;
    if(n==2||n==5||n==3)return 1;
    if(n%2==0||n%3==0||n%5==0)return 0;
    q=(int)sqrt(n);
    for(;i<=q;){
        for(j=0;j<8;j++){
            if(n%i==0)return 0;
            i+=p[j];
        }
        if(n%i==0)return 0;
    }
    return 1;
}
int main()
{
    long long n;
    long long a,b;
    scanf("%lld",&n);
    while(n--)
    {
        scanf("%lld%lld",&a,&b);
        long long cnt=0;
        for(long long i=a;i<=b;i+=2)
        {
                int m=(i+1)/2;
                if((prime(i)==1)&&(prime(m)==1))
                   {
                       cnt++;
                   }

        }
        printf("%lld\n",cnt);
        cnt=0;
    }
    return 0;
}