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<string>
#include<vector>
#include<utility>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<complex>
#define INF 2147483647
#define llINF 9223372036854775807
#define pb push_back
#define mp make_pair 
#define F first
#define S second
#define ll long long

using namespace std;
int main(){
  int n,m;
  while(cin>>n>>m,n+m){
    int r,q;
    cin>>r;
    int stu[m+10][550]={};
    for(int i=0;i<r;i++){
      int a,b,c,d;
      cin>>a>>b>>c>>d;
      if(d){
	stu[c][a-540]++;
      }else{
	stu[c][a-540]--;
      }
    }
    int anss[m+10][550]={};
    for(int i=1;i<=m;i++){
      int po=0;
      for(int j=0;j<=521;j++){
	if(j==0&&po>0)anss[i][j]=1;
	else if(j==0&&po<=0)anss[i][j]=0;
	else if(po>0)anss[i][j]=anss[i][j-1]+1;
	else if(po<=0)anss[i][j]=anss[i][j-1];
	//if(i==1)cout<<j<<" "<<anss[1][j]<<endl;
	po+=stu[i][j];
      }
    }
    cin>>q;
    for(int i=0;i<q;i++){
      int fr,to,num;cin>>fr>>to>>num;
      cout<<anss[num][to-540]-anss[num][fr-540]<<endl;
    }
  }
  return 0;
}

C++: #include<cstdio>
#include<stack>
#include<vector>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
typedef pair<int,int> P;
stack<P> stu[10003];
vector<P> vec[10003];
int N,M,r;
int t[1003],n[1003],m[1003],s[1003];
int q;
int qs[55],qe[55],qm[55];
int main(){
  while(1){
    memset(t,0,sizeof(t));
    memset(n,0,sizeof(n));
    memset(m,0,sizeof(m));
    memset(s,0,sizeof(s));
    memset(qs,0,sizeof(qs));
    memset(qe,0,sizeof(qe));
    memset(qm,0,sizeof(qm));
    for(int i=0;i<10003;i++)vec[i].resize(0);
    for(int i=0;i<10003;i++){
      while(1){
        if(!stu[i].empty()) stu[i].pop();
        else break;
      }}

    scanf("%d%d",&N,&M);
    if(N==0 && M==0) break;
    scanf("%d",&r);
    for(int i=0;i<r;i++){
      scanf("%d%d%d%d",&t[i],&n[i],&m[i],&s[i]);
      if(s[i]==1) stu[m[i]].push(P(t[i],n[i]));
      if(s[i]==0) {
        P p=stu[m[i]].top();
        stu[m[i]].pop();
        if(stu[m[i]].empty()) vec[m[i]].push_back(P(p.first,t[i]));
      }
    }
    scanf("%d",&q);
    int i;
    for(i=0;i<q;i++) {
      scanf("%d%d%d",&qs[i],&qe[i],&qm[i]);

      if(vec[qm[i]].empty()) {printf("0\n"); continue;}

      int res=0;
      int start=0,end=vec[qm[i]].size()-1;

      for(int j=0;j<vec[qm[i]].size();j++){
        if(vec[qm[i]][j].first <=qs[i] && vec[qm[i]][j].second >=qs[i]){
          start=j;
        }
        if(vec[qm[i]][j].first <=qe[i] && vec[qm[i]][j].second >=qe[i]){
          end=j;
        }
        }


      for(int g=start;g<end;g++){
        res+=vec[qm[i]][g+1].first-vec[qm[i]][g].second;
      }

      if(qs[i]<vec[qm[i]][0].first) res+=vec[qm[i]][0].first-qs[i];
      if(vec[qm[i]][vec[qm[i]].size()-1].second < qe[i]) res+=qe[i]-vec[qm[i]][vec[qm[i]].size()-1].second;

      printf("%d\n",qe[i]-qs[i]-res);

    }

  }
  return 0;
}