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 <bits/stdc++.h>
using namespace std;

#define iota(i,n,b,s) for(int i=int(b);i!=int((b)+(s)*(n));i+=(s))
#define range(i,n,m) iota(i,(((n)>(m))?((n)-(m)):((m)-(n))),(n),((n)>(m)?-1:1))
#define rep(i,n) iota(i,(n),0,1)
#define loop for(;;)

#define INF (1e9)
#define EPS (1e-9)
#define cons(a,b) (make_pair(a,b))
#define car(a) (a.first)
#define cdr(a) (a.second)
#define cadr(a) (car(cdr(a)))
#define cddr(a) (cdr(cdr(a)))
#define all(a) a.begin(), a.end()
#define trace(var) cerr<<">>> "<<#var<<" = "<<var<<endl;

typedef long long Integer;
typedef double Real;
typedef vector<int> vi;
typedef vector<string> vs;
typedef map<string,int> Dictionary;
const Real PI = acos(-1);

template<class S, class T>
ostream& operator<<(ostream& os, pair<S,T> p) {
  os << '(' << car(p) << ", " << cdr(p) << ')';
  return os;
}

template<class T>
ostream& operator<<(ostream& os, vector<T> v) {
  if (v.size() == 0) {
    os << "(empty)";
    return os;
  }
  os << v[0];
  for (int i=1, len=v.size(); i<len; ++i) os << ' ' << v[i];
  return os;
}

int dx[] = { -1, 0, 1, 0 };
int dy[] = {  0, -1, 0, 1 };

int main() {

  for (int n, m; cin >> n >> m, n && m;) {
    vector<pair<int, pair<int, int>>> ps;
    rep (i, m) {
      int t, s, d; cin >> t >> s >> d;
      --s; --d;
      ps.push_back(cons( t, cons(s, d)));
    }
    sort(all(ps));

    vector<bool> is(n, false);
    is[0] = true;
    for (auto&p : ps) {
      if (is[cadr(p)]) is[cddr(p)] = true;
    }
    int cx = 0;
    rep (i, n) { if (is[i]) ++cx; }
    cout << cx << endl;
  }

  return 0;
}

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

using namespace std;

int main(){
	int n, m;
	bool infect[20001];
	pair< int,pair<int,int> > packet[20000];
	while(cin >> n >> m){
		memset(infect, false, sizeof(infect));
		infect[1] = true;
		for(int i=0;i<m;i++){
			int t, s, d;
			scanf("%d %d %d", &t, &s, &d);
			packet[i] = make_pair(t,make_pair(s,d));
		}
		sort(packet,packet+m);
		for(int i=0;i<m;i++){
			int s = packet[i].second.first;
			int d = packet[i].second.second;
			if(infect[s]) infect[d] = true;
		}
		int ans = 0;
		for(int i=1;i<=n;i++) ans += infect[i];
		cout << ans << endl;
	}
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <set>
#include <queue>
#include <stack>
#include <map>
using namespace std;

#define REP(i, s, e) for (int i = (s); i < (e); i++)
#define REPI(i, s, e) for (int i = (s); i <= (e); i++)
#define rep(i, n) REP(i, 0, n)
#define repi(i, n) REPI(i, 0, n)
#define ALL(v) (v).begin(), (v).end()

#define dump(x) (cout << #x << " = " << x << endl)
#define dump2(x, y) (cout << "(" << #x << ", " << #y << ") = (" << x << ", " << y << ")" << endl)
#define dump3(x, y, z) (cout << "(" << #x << ", " << #y << ", " << #z << ") = (" << x << ", " << y << ", "<< z << ")" << endl)

typedef long long ll;
typedef pair<int, int> pii;

int N, M;

#define MAX 20001
bool connect[MAX][MAX];
bool visit[MAX];

vector<int> path;

void topological_sort(int i)
{
	if (!visit[i]) {
		visit[i] = true;
		rep(j, N)
			if (connect[i][j])
				topological_sort(j);
		path.push_back(i);
	}
}

int main(void)
{
	while (cin >> N >> M, N|M) {
		rep(j, N) rep(i, N) connect[j][i] = false;
		fill(visit, visit+N, false);

		rep(i, M) {
			int t, s, d;
			cin >> t >> s >> d;

			s--, d--;
			connect[s][d] = true;
		}

		path = vector<int>();
		rep(i, N)
			topological_sort(i);

		cout << path[0]+1 << endl;
	}
	return 0;
}

C++: #include<iostream>
#define loop(i,a,b) for(int i=a;i<b;i++)
#define rep(i,a) loop(i,0,a)
using namespace std;

int main(){
	int n,m;
	while(cin>>n>>m,n||m){
		bool infect[n+1];
		rep(i,n+1)infect[i]=false;
		infect[1]=true;
		int t,s,d,ans=1;
		rep(i,m){
			cin>>t>>s>>d;
			if(infect[s]){
				ans++;
				infect[d]=true;
			}
		}
		cout<<ans<<endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
template<class T> inline T sqr(T x) {return x*x;}

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define each(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define exist(s,e) ((s).find(e)!=(s).end())
#define range(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)  range(i,0,n)
#define clr(a,b) memset((a), (b) ,sizeof(a))
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

const double eps = 1e-10;
const double pi  = acos(-1.0);
const ll INF =1LL << 62;
const int inf =1 << 29;

const int nmax=20010;
bool infected[nmax];


int main(void){
	int n,m;
	while(cin >> n >> m){
		if(n==0)
			break;
		rep(i,nmax) infected[i]=false;
		infected[1]=true;
		vector<tuple<int,int,int>> data;

		rep(i,m){
			int t,s,d;
			cin >> t >> s >> d;
			data.push_back(make_tuple(t,s,d));
		}
		sort(data.begin(),data.end());
		rep(i,data.size()){
			int t,s,d;
			tie(t,s,d)=data[i];
			if(infected[s])
				infected[d]=true;
		}
		int ans=0;
		range(i,1,n+1) ans+=infected[i];
		cout << ans << endl;
	}
	return 0;
}