Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		_, M := io.NextInt(), io.NextInt()
		if M == 0 {
			break
		}
		r := io.NextInt()
		t, m, s := make([]int, r), make([]int, r), make([]int, r)
		for i := 0; i < r; i++ {
			t[i], _, m[i], s[i] = io.NextInt(), io.NextInt(), io.NextInt()-1, io.NextInt()
		}
		q := io.NextInt()
		for i := 0; i < q; i++ {
			ss, ee, mm := io.NextInt(), io.NextInt(), io.NextInt()-1
			x := make([]int, 1300)
			for j := 0; j < r; j++ {
				if m[j] == mm {
					if s[j] == 1 {
						x[t[j]]++
					} else {
						x[t[j]]--
					}
				}
			}
			for j := 1; j < 1300; j++ {
				x[j] = x[j] + x[j-1]
			}
			ans := 0
			for j := ss; j < ee; j++ {
				if x[j] > 0 {
					ans++
				}
			}
			io.Println(ans)
		}
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio> 
#include <cstring>

#define rep(i, n) for(int (i) = 0; (i) < (n); (i)++)
#define rangeRep(i, n, m) for(int (i) = (n); (i) < (m); (i)++)
struct Student {
	int t, n, m, s;
};

constexpr int timeOffset = 540;
//[PC][time] = Student
int use[1000][1260 - timeOffset];


class Solve {
public:
	Solve() {};
	~Solve() {};

	void solver() {
		std::vector<std::vector<int>> results;
		while (1) {
			int n, m, r, q;
			std::cin >> n >> m;
			if (!n) break;

			std::memset(use, 0, sizeof(use));
			results.push_back(std::vector<int>());
			//login info
			std::cin >> r;
			Student s;
			rep(i, r) {
				//time, PC, student, isLogin
				std::cin >> s.t >> s.n >> s.m >> s.s;
				//login
				if (s.s) {
					//set login start time
					use[s.n - 1][s.t - timeOffset] = s.m;
				}//logout
				else {
					//Fill until login start time
					int time = s.t - timeOffset - 1;
					while (use[s.n - 1][time] == 0) {
						use[s.n - 1][time--] = s.m;
					} 
				}
			}

			//question [ts, te]
			std::cin >> q;
			rep(i, q) {
				int num = 0;
				int ts, te, m;
				std::cin >> ts >> te >> m;
				ts -= timeOffset; te -= timeOffset;
				//Check if logged in on any PC.
				rangeRep(j, ts, te) {
					rep(k, n) {
						if (use[k][j] == m) {
							num++;
							break;
						}
					}
				}
				results.back().push_back(num);
			}
		}

		for (auto& x : results) {
			for (auto& y : x) {
				std::cout << y << std::endl;
			}
		}
	}
private:

};

int main() {
	Solve solve;
	solve.solver();
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

#define MAX 1100

int main(){

  while(1){
    int N,M, r, q, time[MAX][2000] = {};
    int t, n, m, s, ts, te, temp;
    cin>>N>>M;
    if(!N&&!M)break;
    cin>>r;
    for(int i = 1; i <= r; i++){
      cin>>t>>n>>m>>s;
      if(!s){
	time[n][t+1] -= m;
      }else {
	time[n][t] += m;
      }
    }

    for(int j = 540; j <= 1260; j++){
      for(int k = 1; k <= N; k++){//cout<<time[k][j]<<" ";cout<<endl;
	time[k][j] += time[k][j-1];
      }
    }
   /* for(int j = 780; j <= 870; j++){cout<<j<<" ";
      for(int k = 1; k <= N; k++)cout<<time[k][j]<<" ";cout<<endl;
    }*/
 
    cin>>q;
    for(int i = 1; i <= q; i++){
      int ans = 0, temp = 0;
      cin>>ts>>te>>m;
      for(int j = ts; j <= te; j++){
	for(int k = 1; k <= N; k++){
	  int l = j;
	  if(time[k][j] == m){//cout<<k<<" "<<j<<" "<<m<<endl;
	    while(time[k][l] && l <= te)l++;
	    ans += l-j-1; //cout<<ans<<" "<<l<<" "<<j<<endl;
	    if(temp == j-1)ans++; 
	    j = l-1;
	    temp = j;
	    break;
	  }
	}
      }
      cout<<ans<<endl;
    }
  }

  return 0;
}

C++: //#include <bits/stdc++.h>
#include<iostream>
#include<stdio.h>
#include<bitset>
#include<algorithm>
#include<vector>
#include<list>
#include<queue>
#include<stack>
#include<string>
#include<string.h>
#include<cmath>
#include<utility>
#include<functional>
#include<map>
#include<set>


#define FOR(i, a, b) for(long long int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LLINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979

using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;


int main(void) {

	while (1) {
		int N, M, r, q;
		int t, n, m, s;
		int ts, te;

		cin >> N >> M;
		if (N == 0) {
			break;
		}
		vector <vector <int> > dp(M + 1, vector<int>(723, 0));

		cin >> r;
		FOR(i, 1, r) {
			cin >> t >> n >> m >> s;
			if (s == 0) {
				dp[m][t - 538]--;
			}
			else {
				dp[m][t - 539]++;
			}
		}
		FOR(i, 1, M) {
			FOR(j, 1, 722) {
				dp[i][j] += dp[i][j - 1];
			}
		}
		cin >> q;
		FOR(i, 1, q) {
			int total = 0;
			int first = -1, end = -1;
			cin >> ts >> te >> m;
			FOR(j, ts - 539, te - 539) {
				if (first == -1 && dp[m][j] >= 1) {
					first = j;
				}
				if (first != -1 && dp[m][j] <= 0) {

					end = j;
					//cout << "a" << first + 539 << " " << end + 539 << endl;
					total += end - first - 1;
					first = -1;
					end = -1;
				}
				if (j == te - 539 && first != -1) {
					//cout << "b" << first + 539 << " " << j + 539 << endl;
					total += j - first;
				}
			}
			cout << total << endl;
		}
	}

	return 0;
}

C++: #include <iostream>
#define R 1000
#define TMAX 1261
using namespace std;
int main(){
  int N,M,r,q,t[R],n[R],m[R],s[R],end[R],ts,te,m1,cnt,lim,time[TMAX];
  while(1){
    cin >> N >> M;
    if(N==0&&M==0) break;
    cin >> r;
    for(int i=0;i<r;i++){
      cin >> t[i] >> n[i] >> m[i] >> s[i];
    }
    cin >> q;
    for(int i=0;i<q;i++){
      cin >> ts >> te >> m1;
      for(int j=ts;j<=te;j++){
	time[j]=0;
      }
      for(int j=0;j<r;j++) end[j]=0;
      cnt=0;
      for(int j=0;j<r;j++){
	if(end[j]==0){
	  end[j]=1;
	  if(m1==m[j]){
	    for(int k=j+1;k<r;k++){
	      if(m1==m[k]&&n[j]==n[k]&&end[k]==0){
		end[k]=1;
		for(int l=t[j]+1;l<=t[k];l++){
		  if(time[l]==0&&ts<l&&l<=te){
		    time[l]=1;
		    cnt++;
		  }
		}
		break;
	      }
	    }
	  }
	}
      }
      cout << cnt << endl;
    }
  }
  return 0;
}