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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
static class Program{
	const int mod=(int)1e9+7;
	static void Main(){
		Sc sc=new Sc();
		var s=sc.Ia;
		Fc fc=new Fc(s[0]+1);
		for(int i = 0;i<s[1];i++) {
			var e=sc.Ia;
			fc.Ud(e[0],e[1]);
		}
		fc.Dn();
		StringBuilder sb=new StringBuilder();
		for(int i = 0;i<s[2];i++) {
			var e=sc.Ia;
			sb.Append(fc.Get(e[0],e[1],e[0],e[1])+"\n");
		}
		Console.Write(sb);
	}
}
public class Fc{
	private List<Tuple<int,int,int>>[] dat;
	private int m=1,cnt=0;
	public Fc(int n){
		while(m<n){m<<=1;}
		cnt=m+n-1;
		dat=new List<Tuple<int,int,int>>[cnt];
		for(int i = m-1;i<cnt;i++) {dat[i]=new List<Tuple<int,int,int>>();}
	}
	public long Get(int x1,int x2,int y1,int y2){
		int lb=-1,ub=dat[0].Count,mid=0;
		while(ub-lb>1){
			mid=(ub+lb)/2;
			if(dat[0][mid].Item1>y2){ub=mid;}
			else{lb=mid;}
		}
		int p=ub;
		lb=-1;ub=dat[0].Count;
		while(ub-lb>1){
			mid=(ub+lb)/2;
			if(dat[0][mid].Item1>=y1){ub=mid;}
			else{lb=mid;}
		}
		return Fdg(x1,x2,0,0,m-1,ub,p);
	}
	private long Fdg(int a,int b,int k,int l,int r,int la,int ra){
		if(r<a||b<l||ra==la){return 0;}
		if(a<=l&&r<=b){
			return ra-la;
		}
		else{return Fdg(a,b,k*2+1,l,(l+r)>>1,dat[k][la].Item2,dat[k][ra].Item2)+Fdg(a,b,k*2+2,(l+r+1)>>1,r,dat[k][la].Item3,dat[k][ra].Item3);}
	}
	public void Ud(int x,int y){dat[x+m-1].Add(Tuple.Create(y,-1,-1));}
	public void Dn(){
		for(int i = m-1;i<cnt;i++) {
			dat[i].Sort();
		}
		for(int i = m-2;i>=0;i--) {
			if((i<<1)+2<cnt){
				dat[i]=new List<Tuple<int,int,int>>();
				int j=0,k=0;
				while(j<dat[(i<<1)+1].Count&&k<dat[(i<<1)+2].Count){
					if(dat[(i<<1)+1][j].Item1<dat[(i<<1)+2][k].Item1){dat[i].Add(Tuple.Create(dat[(i<<1)+1][j].Item1,j,k));j++;}
					else{dat[i].Add(Tuple.Create(dat[(i<<1)+2][k].Item1,j,k));k++;}
				}
				while(j<dat[(i<<1)+1].Count){dat[i].Add(Tuple.Create(dat[(i<<1)+1][j].Item1,j,k));j++;}
				while(k<dat[(i<<1)+2].Count){dat[i].Add(Tuple.Create(dat[(i<<1)+2][k].Item1,j,k));k++;}
			}
			else if((i<<1)+1<cnt){
				dat[i]=new List<Tuple<int,int,int>>();
				for(int j = 0;j<dat[(i<<1)+1].Count;j++) {dat[i].Add(Tuple.Create(dat[(i<<1)+1][j].Item1,j,-1));}
			}
			else{dat[i]=new List<Tuple<int,int,int>>();}
		}
		for(int i = 0;i<m-1;i++) {
			if((i<<1)+2<cnt){
				dat[i].Add(Tuple.Create(int.MaxValue,dat[(i<<1)+1].Count,dat[(i<<1)+2].Count));
			}
			else if((i<<1)+1<cnt){
				dat[i].Add(Tuple.Create(int.MaxValue,dat[(i<<1)+1].Count,-1));
			}
		}
	}
}

public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),int.Parse);}
	public int[] Ia3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(int a){return Array.ConvertAll((a.ToString()+" "+Console.ReadLine()).Split(),long.Parse);}
	public long[] La3(bool a,int b,bool c,int d){return Array.ConvertAll(((a?b.ToString()+" ":"")+Console.ReadLine()+(c?" "+d.ToString():"")).Split(),long.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}