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 <string.h>
#define MAX 100005

int Q;
int l[MAX], r[MAX];

int checkPrime(int n)
{
	int i, cnt, rev;
	i = 1; cnt = 0;
	while (i<=n){
		if (n%i == 0) cnt++;
		i++;
	}
	if (cnt == 2) rev = 1;
	else rev = 0;
	return rev;
}
int checkSimilar(int n){
	int rev;
	int A = checkPrime(n);
	int B = checkPrime((n + 1) / 2);
	if (A&&B) rev = 1;
	else rev = 0;
	return rev;
}
void printRe(int i)
{
	int k, cnt;
	cnt = 0;
	for (k = l[i]; k <= r[i]; k++){
		if (checkSimilar(k)) cnt++;
	}
	printf("%d\n", cnt);
}

int main(void)
{
	scanf("%d", &Q);
	int i;
	for (i = 1; i <= Q; i++){
		scanf("%d%d", &l[i], &r[i]);
	}
	for (i = 1; i <= Q; i++){
		printRe(i);
	}
	return 0;
}