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 <stdlib.h>
struct LR{
        int L;
        int R;
}lr[200000];
int A[500][500];
int comp(const void *A, const void *B){
        struct LR *a=A,*b=B;
        if(a->L == b->L)
                return a->R - b->R;

        return a->L - b->L;
}
main(){
        int N,M,Q;
        scanf("%d %d %d",&N,&M,&Q);

        int i,j,k;
        for(i=0;i<N;i++)
                for(j=0;j<N;j++)
                        A[i][j]=0;

        for(i=0;i<M;i++){
                scanf("%d %d",&lr[i].L,&lr[i].R);
        }
        qsort(lr,M,sizeof(struct LR),comp);
        for(i=0;i<M;i++){
                for(j=0;j<=lr[i].L-1;j++){
                        for(k=lr[i].R-1;k<=N-1;k++){
                                A[j][k]++;
                        }
                }
        }
        int p,q;
        for(i=0;i<Q;i++){
                scanf("%d %d",&p,&q);
                printf("%d\n",A[p-1][q-1]);
        }
        return 0;

}