Go: package main

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

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		n, m := io.NextInt(), io.NextInt()
		if n == 0 {
			break
		}
		dat := make([]Dat, m)
		for i := 0; i < m; i++ {
			dat[i] = Dat{io.NextInt(), io.NextInt(), io.NextInt()}
		}
		sort.Slice(dat, func(i, j int) bool { return dat[i].t < dat[j].t })
		infected := make([]bool, n+1)
		infected[1] = true
		for i := 0; i < m; i++ {
			infected[dat[i].d] = infected[dat[i].d] || infected[dat[i].s]
		}
		cnt := 0
		for i := 0; i <= n; i++ {
			if infected[i] {
				cnt++
			}
		}
		io.Println(cnt)
	}
}

type Dat struct {
	t, s, d int
}

// 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 := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := make([]interface{}, 0, len(a))
	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>
using namespace std;

struct Data{
  
  int t,s,d;

  bool operator<(const Data& data)const{
    if(data.t != t)return t < data.t;  
    if(data.s != s)return s < data.s;
    return d < data.d;
  }
  
};
int main(){

  int N,M;
  
  while(1){

    cin >>N>>M;
    if(N==0 && M==0)break;
    
    Data data[M];
    for(int i=0 ; i < M ; i++){
      cin >>data[i].t>>data[i].s>>data[i].d;
    }
    
    sort(data,data+M);
    
    bool isinfected[N+1];
    for(int i=1 ; i <= N ; i++)isinfected[i]=false;
    isinfected[1]=true;
    
    int cnt=1;
    for(int i=0 ; i < M ; i++){
      if(isinfected[data[i].s] && !isinfected[data[i].d]){
	isinfected[data[i].d]=true;
	cnt++;
      }
    }
    
    cout <<cnt<<endl;
    
  }
  
  return 0;
}

C++: #include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
using namespace std;

struct list{
	int t;
	int s;
	int d;
};
struct list l[20010];
int v[20010];
int n, m, ans;


class LessAn{
public:
	bool operator()(const list& a, const list& b){
		return a.t < b.t;
	}
};
	

int main(void){
	int i;
	while( cin >> n >> m, n){
		ans = 0;
		memset(l, 0, sizeof(l));
		memset(v, 0, sizeof(v));
		for(i = 0; i < m; i++) cin >> l[i].t >> l[i].s >> l[i].d;
		sort(l, l + m, LessAn());
		v[1] = 1;
		for(i = 0; i < m; i++) if(v[l[i].s]) v[l[i].d] = 1;
		for(i = 1; i <= n; i++) if(v[i]) ans++;
		cout << ans << endl;
	}
	return 0;
}

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

struct Data{
  
  int t,s,d;

  bool operator<(const Data& data)const{
    if(data.t != t)return t < data.t;  
    if(data.s != s)return s < data.s;
    return d < data.d;
  }
  
};
int main(){

  int N,M;
  
  while(1){

    cin >>N>>M;
    if(N==0 && M==0)break;
    
    Data data[M];
    for(int i=0 ; i < M ; i++){
      cin >>data[i].t>>data[i].s>>data[i].d;
    }
    
    sort(data,data+M);
    
    bool isinfected[N+1];
    for(int i=1 ; i <= N ; i++)isinfected[i]=false;
    isinfected[1]=true;
    
    int cnt=1;
    for(int i=0 ; i < M ; i++){
      if(isinfected[data[i].s] && !isinfected[data[i].d]){
	isinfected[data[i].d]=true;
	cnt++;
      }
    }
    
    cout <<cnt<<endl;
    
  }
  
  return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

int main(){
  long long int n,m,i, k;
  while(cin >> n >> m, n != 0 || m != 0) {
    vector<long long int> v(20100);
    long long int cnt = 1, data[20100][10] = {};
    long long int in[20100] = {};
    in[1] = 1;
    k = 0;
    for(i = 0; i < m; i++) {
      long long int t,s,g;
      cin >> t >> s >> g;
      data[t][0] = s;
      data[t][1] = g;
      v[k++] = t;
    }
    sort(v.begin(), v.begin() + m);
    for(i = 0; i < m; i++) {
      if(in[data[v[i]][0]]){
	  if(in[data[v[i]][1]] == 0)
	    {
	      cnt++;
	      in[data[v[i]][1]] = 1;
	    }
	}
    }
      
    cout << cnt << endl;
  }
  return 0;
}

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

int N, M;
vector< vector< pair<int, int> > > v;
vector<bool> used;

int dfs(int pos, int time){
    
    used[pos] = true;
    int res = 0;
    for(int i = 0; i < v[pos].size(); i++){
        if(used[ v[pos][i].second ] == true) continue;
        if(v[pos][i].first > time){
            res += dfs(v[pos][i].second, v[pos][i].first);
        }
    }

    return res + 1;
}

int main(void){
    while(cin >> N >> M, N | M){
        v = vector<vector<pair<int, int> > >(N, vector< pair<int, int> >(0));
        used = vector<bool>(N, false);
        for(int i = 0; i < M; i++){
            int t, s, d; cin >> t >> s >> d;
            s--; d--;
            v[s].push_back(make_pair(t, d));
        }
        cout << dfs(0, 0) << endl;
    }
    return 0;
}

C++: #include <vector>
#include <iostream>
#include <utility>
#include <algorithm>
#include <string>
#include <deque>
#include <queue>
#include <tuple>
#include <queue>
#include <functional>
#include <cmath>
#include <iomanip>
#include <map>
#include <set>
#include <numeric>
#include <unordered_map>
#include <unordered_set>
#include <complex>
#include <iterator>
#include <array>
#include <memory>
#include <stack>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
template<class T, class S> void cmin(T &a, const S &b) { if (a > b)a = b; }
template<class T, class S> void cmax(T &a, const S &b) { if (a < b)a = b; }
#define MAX 9999999
using namespace std;
typedef pair<int, pair<int,int>> pii;
typedef pair<double,double>pdd;
typedef pair<ll,ll>pll;
int main(){
    int a,b;
    while(cin>>a>>b,a+b){
        map<int,int>mp;
        mp[1]=1;
        vector<pii>hoge;
        rep(i,b){
            pii temp; cin>>temp.first>>temp.second.first>>temp.second.second;
            hoge.push_back(temp);
            
        }
        sort(all(hoge));
        rep(i,hoge.size()){
            if(mp[hoge[i].second.first])mp[hoge[i].second.second]++;
            //if(mp[hoge[i].second.second])mp[hoge[i].second.first]++;
        }
        int ans=0;
        for(int i=1; i<=a;i++)
            if(mp[i])ans++;
        cout<<ans<<endl;
    }
}