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: Runtime Error)


#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

int main(void){
bool prime[100001]={true};
prime[0]=prime[1]=false;
int i,j,k,m,Q;
vector<int>l(Q);
vector<int>r(Q);
for(i=2;i<=316;i++){
if(prime[i]){
for(j=2*i;j<=100000;j+=i){
prime[j]=false;
}}}
int ans[100001]={};
for(i=1;i<=100000;i+=2){
if(prime[i]&&prime[(i+1)/2]){
ans[i]=ans[i-2]+1;
}}
cin>>Q;
for(i=0;i<=Q-1;i++){
cin>>l[i]>>r[i];
}
for(i=0;i<=Q-1;i++){
cout<<ans[r[i]]-ans[l[i]]<<endl;
}
return 0;
}