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)

#![allow(unused)]

use std::{cell, cmp, collections, fmt, ops};

use cell::{Cell, RefCell};
use cmp::Ordering::{Equal, Greater, Less};
use collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
use fmt::{Debug, Display};

#[cfg(feature = "debug")]
macro_rules! debug {
    ($($args: tt)*) => { eprint!($($args)*) };
}

#[cfg(feature = "debug")]
macro_rules! debugln {
    ($($args: tt)*) => { eprintln!($($args)*) };
}

#[cfg(not(feature = "debug"))]
macro_rules! debug {
    ($($args:tt)*) => {};
}

#[cfg(not(feature = "debug"))]
macro_rules! debugln {
    ($($args:tt)*) => {};
}

macro_rules! vmin {
    ($x: expr, $y: expr) => { cmp::min($x, $y) };
    ($x: expr, $($args: expr),*) => { cmp::min($x, vmin!($($args),*)) };
}

macro_rules! vmax {
    ($x: expr, $y: expr) => { cmp::max($x, $y) };
    ($x: expr, $($args: expr),*) => { cmp::max($x, vmax!($($args),*)) };
}

fn main() {
    use io::*;

    const N: usize = 500;

    let (_, m, q) = {
        let nmq = parse_vec::<usize>();
        (nmq[0], nmq[1], nmq[2])
    };

    // #Trains running range [i, j]
    let mut trains_num = [[0; N + 1]; N + 1];
    for _ in 0..m {
        let lr = parse_vec::<usize>();
        trains_num[lr[0]][lr[1]] += 1;
    }

    // Cumulative #trains running in range [i, 1], [i, 2], .., [i, j]
    let mut trains_num_cum = [[0; N + 1]; N + 1];
    for i in 1..(N + 1) {
        trains_num_cum[i][1] = trains_num[i][1];
        for j in 2..(N + 1) {
            trains_num_cum[i][j] = trains_num_cum[i][j - 1] + trains_num[i][j];
        }
    }

    for _ in 0..q {
        let query = parse_vec::<usize>();
        let ans = (query[0]..(query[1] + 1))
            .map(|i| trains_num_cum[i][query[1]] - trains_num_cum[i][query[0] - 1])
            .sum::<usize>();

        println!("{}", ans);
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test() {
        //
    }
}

mod io {
    use std::io::{self, Read, Write};
    use std::str;

    pub fn read_line() -> String {
        let mut buf = String::new();
        io::stdin().read_line(&mut buf).unwrap();
        buf.trim().to_owned()
    }

    pub fn read_word() -> String {
        const CAPACITY: usize = 16;

        let mut stdin = io::stdin();
        let mut byte: [u8; 1] = [0];

        loop {
            let mut buf = Vec::with_capacity(CAPACITY);

            loop {
                let res = stdin.read(&mut byte);

                if res.unwrap_or(0) == 0 || byte[0] <= b' ' {
                    break;
                } else {
                    buf.push(byte[0]);
                }
            }

            if !buf.is_empty() {
                return String::from_utf8(buf).unwrap();
            }
        }
    }

    pub fn parse_line<T: str::FromStr>() -> T {
        read_line().parse().ok().unwrap()
    }

    pub fn parse_word<T: str::FromStr>() -> T {
        read_word().parse().ok().unwrap()
    }

    pub fn parse_vec<T: str::FromStr>() -> Vec<T> {
        read_line()
            .split_whitespace()
            .map(|e| e.parse().ok().unwrap())
            .collect()
    }

    pub fn flush() {
        io::stdout().flush();
    }
}

mod num {
    use std::{cmp, ops};

    pub fn imin<T, I>(v: &T) -> &I
    where
        T: ops::Deref<Target = [I]>,
        I: cmp::Ord + Copy,
    {
        v.iter().min().unwrap()
    }

    pub fn imax<T, I>(v: &T) -> &I
    where
        T: ops::Deref<Target = [I]>,
        I: cmp::Ord + Copy,
    {
        v.iter().max().unwrap()
    }

    pub fn next_prime(x: i32) -> i32 {
        for i in (x + 1).. {
            if is_prime(i) {
                return i;
            }
        }

        panic!("attempt to add with overflow");
    }

    pub fn is_prime(x: i32) -> bool {
        let ceil = f64::from(x).sqrt().ceil() as i32;
        x == 2 || (2..(ceil + 1)).all(|i| x % i != 0)
    }
}

mod bits {
    pub fn bit_high(bits: u64, pos: u64) -> bool {
        bits & (1 << pos) != 0
    }
}