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 Python (3.4.3) (judge verdict: Runtime Error)

from operator import itemgetter

n, m, q = map(int, input().split())

trains = []
for i in range(m):
  a, b = map(int, input().split())
  trains.append((a,b))

trains.sort(key=itemgetter(1))
trains.sort(key=itemgetter(0))
index = [-1 for _ in range(n+1)]
index[trains[0][0]] = 0
tmp = trains[0][0]

num = 0
for i in range(1, len(trains)):
  i -= num
  if trains[i] == trains[i-1]:
    del trains[i]
    num += 1
  if tmp != trains[i][0]:
    tmp = trains[i][0]
    index[tmp] = i
    
for i in range(len(index)-2, 0, -1):
    if index[i] == -1:
      index[i] = index[i+1]

questions = []
for i in range(q):
  a, b = map(int, input().split())
  questions.append((i,a,b))
  
questions.sort(key=itemgetter(1))

for question in questions:
  cnt = 0
  for train in trains[index[question[1]]:]:
    if train[1] > question[1]:
      continue
    cnt += 1
    
  print(cnt)