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: Time Limit Exceeded)

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

#define rep(i,begin,end) for(int i=begin; i<end; i++)
#define revrep(i,begin,end) for(int i=begin; i>end; i--)
#define lld long long int

typedef struct node{
    int l, r;
}node;

int cmpAsc(const void* a, const void* b){
    int x = ((node*)a)->r, y = ((node*)b)->r;
    if(x > y){
        return 1;
    }
    if(x < y){
        return -1;
    }
    return 0;
}

int main(){
    int n, m, q;
    scanf("%d %d %d", &n, &m, &q);
    node a[m];
    rep(i, 0, m){
        int l, r;
        scanf("%d %d", &l, &r);
        a[i].l = l;
        a[i].r = r;
    }
    qsort(a, m, sizeof(node), cmpAsc);
    int ans[q];
    rep(i, 0, q){
        int l, r;
        scanf("%d %d", &l, &r);
        int last = m-1;
        while(0 <= last && r < a[last].r){
            last--;
        }
        int cnt = 0;
        if(last >= 0){
            rep(j, 0, last+1){
                if(l <= a[j].l){
                    cnt++;
                }
            }
        }
        ans[i] = cnt;
    }
    rep(i, 0, q){
        printf("%d\n", ans[i]);
    }

    return 0;
}