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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = int.Parse(line[0]);
        var m = int.Parse(line[1]);
        var q = int.Parse(line[2]);
        var a = new int[n, n];
        for (int i = 0; i < m; i++)
        {
            line = Console.ReadLine().Trim().Split(' ');
            var wh = int.Parse(line[0]) - 1;
            var ww = int.Parse(line[1]) - 1;
            a[wh, ww]++;
        }
        var b = setArray(a);
        for (int i = 0; i < q; i++)
        {
            line = Console.ReadLine().Trim().Split(' ');
            var p = int.Parse(line[0]) - 1;
            var p2 = int.Parse(line[1]) - 1;
            Console.WriteLine(getAns(b, p, p2, n));
        }
    }
    public static int getAns(int[,] a, int p, int q, int n)
    {
        var a1 = 0; var a2 = 0; var a3 = 0; var a4 = 0;
        a1 = a[q, q];
        if (p - 1 >= 0) { a4 = a[p - 1, p - 1]; a2 = a[q, p - 1]; a3 = a[p - 1, q]; }
        return a1 - a2 - a3 + a4;
    }
    public static int[,] setArray(int[,] a)
    {
        var n = a.GetLength(0);
        var t = new int[n, n];
        for (int i = 0; i < n; i++)
        {
            t[i, 0] = a[i, 0];
            for (int j = 1; j < n; j++)
                t[i, j] = t[i, j - 1] + a[i, j];
        }
        var t2 = new int[n, n];
        for (int i = 0; i < n; i++)
        {
            t2[0, i] = t[0, i];
            for (int j = 1; j < n; j++)
                t2[j, i] = t2[j - 1, i] + t[j, i];
        }
        return t2;
    }
}