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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define BUF_SIZE 30

// size: specify sizeof(str)
int get_str(char *str, int size) {
    if(!fgets(str, size, stdin)) return -1;
    return 0;
}

int get_int(void) {
  int num;
#ifdef BUF_SIZE
  char line[BUF_SIZE];
  if(!fgets(line, BUF_SIZE, stdin)) return 0;
  sscanf(line, "%d", &num);
#else
#error
#endif
  return num;
}

int get_int2(int *a1, int *a2) {
#ifdef BUF_SIZE
  char line[BUF_SIZE];
  if(!fgets(line, BUF_SIZE, stdin)) return -1;
  sscanf(line, "%d %d", a1, a2);
#else
#error
#endif
  return 0;
}

int get_int3(int *a1, int *a2, int *a3) {
#ifdef BUF_SIZE
  char line[BUF_SIZE];
  if(!fgets(line, BUF_SIZE, stdin)) return -1;
  sscanf(line, "%d %d %d", a1, a2, a3);
#else
#error
#endif
  return 0;
}

struct range {
    int start;
    int end;
};

#define TRAINS_MAX 200000
#define TOWNS_MAX 500
#define QUERIES_MAX 100000

int main(void) {
    int towns, trains, queries;
    get_int3(&towns, &trains, &queries);
    int i, j;
    static int map[TOWNS_MAX+1][TOWNS_MAX+1];

    static int cum_row[TOWNS_MAX+1][TOWNS_MAX+1];
    static int cum_col[TOWNS_MAX+1][TOWNS_MAX+1];
    for(i = 0; i < trains; i++) {
        struct range r;
        get_int2(&r.start, &r.end);
        map[r.start][r.end]++;
    }

    for(i = 1; i <= towns; i++) {
        for(j = 1; j <= towns; j++) {
            cum_col[i][j] = cum_col[i][j-1] + map[i][j];
        }
    }
    for(j = 1; j <= towns; j++) {
        for(i = 1; i <= towns; i++) {
            cum_row[i][j] = cum_row[i-1][j] + map[i][j];
        }
    }

    // cumulative
    for(i = 1; i <= towns; i++) {
        for(j = 1; j <= towns; j++) {
            map[i][j] = map[i-1][j-1] + cum_col[i][j] + cum_row[i][j] - map[i][j];
        }
    }

    int ans[QUERIES_MAX];
    int ans_idx = 0;
    for(i = 0; i < queries; i++) {
        int src, dst;
        get_int2(&src, &dst);
        ans[ans_idx++] = map[dst][dst] - map[src-1][dst] - map[dst][src-1] + map[src-1][src-1];
    }
    for(i = 0; i < ans_idx; i++) {
        printf("%d\n", ans[i]);
    }
    return 0;
}