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: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <ctype.h>

char buf[100001];

int main(void)
{
  char s[1000];
  int n,i,j,l,r,c,x;
  fgets(s,1000,stdin);
  sscanf(s,"%d",&n);
  memset(buf,0,sizeof(buf));
  for(i=3;i<50000;i+=2){
    if(buf[i]==1) continue;
    for(j=3*i;j<100001;j+=i*2){
      buf[j]= 1;
    }
  }
  
  for(i=0;i<n;i++){
    fgets(s,1000,stdin);
    sscanf(s,"%d %d",&l,&r);
    c = 0;
    for(j=l;j<=r;j+=2){
      x = (j+1)/2;
      if( (x&1) == 1 || x <= 3 ){
        if(buf[j]==0 && ( buf[x] == 0 || x<=3 ) ) c++;
      }
    }
    printf("%d\n",c);
  }
  return EXIT_SUCCESS; 
}