Problem:
Score: 400 points

Problem Statement

In Takahashi Kingdom, there is a east-west railroad and N cities along it, numbered 1, 2, 3, ..., N from west to east.
A company called AtCoder Express possesses M trains, and the train i runs from City L_i to City R_i (it is possible that L_i = R_i).
Takahashi the king is interested in the following Q matters:

The number of the trains that runs strictly within the section from City p_i to City q_i, that is, the number of trains j such that p_i \leq L_j and R_j \leq q_i.

Although he is genius, this is too much data to process by himself. Find the answer for each of these Q queries to help him.

Constraints

N is an integer between 1 and 500 (inclusive).

M is an integer between 1 and 200 \ 000 (inclusive).

Q is an integer between 1 and 100 \ 000 (inclusive).

1 \leq L_i \leq R_i \leq N (1 \leq i \leq M)

1 \leq p_i \leq q_i \leq N (1 \leq i \leq Q)

Input

Input is given from Standard Input in the following format:

N M Q
L_1 R_1
L_2 R_2
:
L_M R_M
p_1 q_1
p_2 q_2
:
p_Q q_Q

Output

Print Q lines. The i-th line should contain the number of the trains that runs strictly within the section from City p_i to City q_i.

Sample Input 1

2 3 1
1 1
1 2
2 2
1 2

Sample Output 1

3

As all the trains runs within the section from City 1 to City 2, the answer to the only query is 3.

Sample Input 2

10 3 2
1 5
2 8
7 10
1 7
3 10

Sample Output 2

1
1

The first query is on the section from City 1 to 7. There is only one train that runs strictly within that section: Train 1.
The second query is on the section from City 3 to 10. There is only one train that runs strictly within that section: Train 3.

Sample Input 3

10 10 10
1 6
2 9
4 5
4 7
4 7
5 8
6 6
6 7
7 9
10 10
1 8
1 9
1 10
2 8
2 9
2 10
3 8
3 9
3 10
1 10

Sample Output 3

7
9
10
6
8
9
6
7
8
10

Solution in Rust (1.42.0) (judge verdict: Accepted)

use std::io;
use std::str::FromStr;
use std::collections::BinaryHeap;

type Pair = (u64, u64);

fn input_tuple() -> (u64, u64) {
    let mut line: String = String::new();
    io::stdin().read_line(&mut line);
    let vec: Vec<u64> = line.split_whitespace().map(|s| s.parse().unwrap()).collect();
    (vec[0], vec[1])
}

fn input_tuple_three() -> (u64, u64, u64) {
    let mut line: String = String::new();
    io::stdin().read_line(&mut line);
    let vec: Vec<u64> = line.split_whitespace().map(|s| s.parse().unwrap()).collect();
    (vec[0], vec[1], vec[2])
}

fn main() {
    let (n, m, q) = input_tuple_three();
    let mut regions: Vec<Vec<u64>> = vec![Vec::new(); n as usize];
    let mut sum: Vec<Vec<u64>> = vec![Vec::new(); n as usize];
    for _ in 0..m {
        let (l, r) = input_tuple();
        regions[l as usize - 1].push(r - 1);
    }
    for i in 0..n as usize {
        let mut queue: BinaryHeap<i64> = BinaryHeap::new();
        for j in &regions[i] {
            queue.push(0 - *j as i64);
        }
        let mut prev = 0;
        for j in 0..n {
            if queue.is_empty() || 0 - j as i64 > *queue.peek().unwrap() {
                sum[i].push(prev);
                continue;
            }
            while !queue.is_empty() && 0 - j as i64 <= *queue.peek().unwrap() {
                queue.pop();
                prev += 1;
            } 
            sum[i].push(prev);
        }
    }
    // println!("{:?}", sum);

    for _ in 0..q {
        let (l, r) = input_tuple();
        let mut ans = 0;
        for j in (l-1)..n {
            ans += sum[j as usize][r as usize - 1];
        }
        println!("{}", ans);
    }
}