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::prelude::*;

fn input<T>() -> T
where
    T: std::str::FromStr,
{
    let stdin = std::io::stdin();
    let token = stdin
        .lock()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>();
    token.parse().ok().unwrap()
}

fn main() {
    let n = input::<usize>();
    let m = input::<usize>();
    let nq = input::<usize>();
    let (l, r) = (0..m)
        .map(|_| {
            let l = input();
            let r = input();
            (l, r)
        })
        .unzip::<usize, usize, Vec<usize>, Vec<usize>>();
    let (p, q) = (0..nq)
        .map(|_| {
            let p = input();
            let q = input();
            (p, q)
        })
        .unzip::<usize, usize, Vec<usize>, Vec<usize>>();

    let mut sum = vec![vec![0; n + 1]; n + 1];
    for i in 0..m {
        sum[l[i]][r[i]] += 1;
    }
    for i in 0..n {
        for j in 0..n {
            sum[i + 1][j + 1] += sum[i][j + 1] + sum[i + 1][j] - sum[i][j];
        }
    }

    let out = std::io::stdout();
    let mut buf = std::io::BufWriter::new(out.lock());
    for i in 0..nq {
        let ans =
            sum[q[i]][q[i]] - sum[p[i] - 1][q[i]] - sum[q[i]][p[i] - 1] + sum[p[i] - 1][p[i] - 1];
        writeln!(buf, "{}", ans).unwrap();
    }
}