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 Ruby (2.3.3) (judge verdict: Accepted)

def gets; ARGF.gets; end

def main
  n, m, q = gets.split.map(&:to_i)

  # 区間を2次元座標上にマッピングする
  # range_map[L][R]
  # ※l,r は1以上なので 0行/0列 は全て0のまま
  range_map = Array.new(n+1) {Array.new(n+1, 0)}
  m.times do
    l, r = gets.split.map(&:to_i)
    range_map[l][r] += 1
  end

  # 2次元累積和を求める
  1.upto(n) do |l|
    row_sum = 0
    1.upto(n) do |r|
      row_sum += range_map[l][r]
      range_map[l][r] = range_map[l-1][r] + row_sum
    end
  end
  # pp range_map

  # 問題解決
  q.times do
    p, q = gets.split.map(&:to_i)
    ans = range_map[q][q] - range_map[p-1][q] - range_map[q][p-1] + range_map[p-1][p-1]
    puts ans
  end
end

if __FILE__ == $0
  main
end