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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>

using namespace std;

int p[100001];
int l[100000];
int r[100000];

int main()
{
	int Q;
	p[0] = p[1] = 1;
	for (int i = 2; i < 100001; i++) {
		while (p[i]) i++;
		for (int j = i * 2;j < 10001; j += i) p[j] = 1; 
	}
	cin >> Q;
	for (int i = 0; i < Q; i++) {
		cin >> l[i]; cin >> r[i];
	}
	for (int i = 0; i < Q; i++) {
		int res = 0;
		for (int j = l[i]; j <= r[i]; j+= 2) {
			if (p[j] == 0 && p[(j + 1) / 2] == 0) {
				res++;
			}
		}
		cout << res << endl;
	}

	return 0;
}