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 (1.15.1) (judge verdict: Accepted)

use std::io;
use std::str::FromStr;

fn main() {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();
    let mut it = buf.split_whitespace().map(|n| usize::from_str(n).unwrap());
    let (n, m, q) = (it.next().unwrap(), it.next().unwrap(), it.next().unwrap());

    let mut matrix = vec![vec![0; n + 1]; n + 1];
    for _ in 0..m {
        let mut buf = String::new();
        stdin.read_line(&mut buf).ok();
        let mut it = buf.split_whitespace().map(|n| usize::from_str(n).unwrap());
        let (l, r) = (it.next().unwrap(), it.next().unwrap());
        matrix[l][r] += 1;
    }

    let mut sum : Vec<Vec<i64>>= vec![vec![0; n + 1]; n + 1];
    for i in 0..n + 1 {
        for j in 0..n + 1 {
            sum[i][j] = matrix[i][j];
            if j as i32 - 1 >= 0 { sum[i][j] += sum[i][j - 1]; };
            if i as i32 - 1 >= 0 { sum[i][j] += sum[i - 1][j]; };
            if i as i32 - 1 >= 0 && j as i32 - 1 >= 0 { sum[i][j] -= sum[i - 1][j - 1]; };
        }
    }

    for _ in 0..q {
        let mut buf = String::new();
        stdin.read_line(&mut buf).ok();
        let mut it = buf.split_whitespace().map(|n| usize::from_str(n).unwrap());
        let (p, q) = (it.next().unwrap(), it.next().unwrap());
        let cnt = get((p, p), (q, q), &sum);
        println!("{}", cnt);
    }
}

fn get((x1, y1) : (usize, usize), (x2, y2) : (usize, usize), sum : &Vec<Vec<i64>>) -> i64 {
    let mut res : i64 = sum[x2][y2];
    if x1 > 0 { res -= sum[x1 - 1][y2]; };
    if y1 > 0 { res -= sum[x2][y1 - 1]; };
    if x1 > 0 && y1 >0 { res += sum[x1 - 1][y1 - 1]; };
    res
}