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>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <climits>
#include <ctime>
#include <cassert>
using namespace std;

#define rep(i,a,n) for(int (i)=(a); (i)<(n); (i)++)
#define repq(i,a,n) for(int (i)=(a); (i)<=(n); (i)++)
#define repr(i,a,n) for(int (i)=(a); (i)>=(n); (i)--)
#define all(v) begin(v), end(v)
#define pb(a) push_back(a)
#define fr first
#define sc second
#define INF 2000000000
#define int long long int

#define X real()
#define Y imag()
#define EPS (1e-10)
#define EQ(a,b) (abs((a) - (b)) < EPS)
#define EQV(a,b) ( EQ((a).X, (b).X) && EQ((a).Y, (b).Y) )
#define LE(n, m) ((n) < (m) + EPS)
#define LEQ(n, m) ((n) <= (m) + EPS)
#define GE(n, m) ((n) + EPS > (m))
#define GEQ(n, m) ((n) + EPS >= (m))

typedef vector<int> VI;
typedef vector<VI> MAT;
typedef pair<int, int> pii;
typedef long long ll;

typedef complex<double> P;
typedef pair<P, P> L;
typedef pair<P, double> C;

int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
int const MOD = 1000000007;

namespace std {
    bool operator<(const P& a, const P& b) {
        return a.X != b.X ? a.X < b.X : a.Y < b.Y;
    }
}

signed main() {
    int n, m; 
    while(cin >> n >> m, n || m) {
        int t, s[100010], d[100010];
        memset(s, -1, sizeof(s));
        memset(d, -1, sizeof(d));
        rep(i,0,m) {
            cin >> t;
            cin >> s[t] >> d[t];
        }

        bool infect[100010] = {};
        infect[1] = true;
        rep(i,0,100010) {
            if(s[i] == -1) continue;
            if(infect[ s[i] ]) {
                infect[ d[i] ] = true;
            }
        }
        int ans = 0;
        rep(i,0,100010) {
            if(infect[i]) ans++;
        }
        cout << ans << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<vector>
#include<map>
#include<algorithm>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
int main(){
	int n,m,t,s,d;
	while(cin>>n>>m,n){
		vector<pair<int,pair<int,int> > >p(m);
		rep(i,m)cin>>t>>s>>d,p[i]=make_pair(t,make_pair(s-1,d-1));
		sort(p.begin(),p.end());
		bool f[n]; rep(i,n)f[i]=i==0;
		int ans=1;
		rep(i,m)if(f[p[i].second.first]&&!f[p[i].second.second])ans++,f[p[i].second.second]=1;
		cout<<ans<<endl;
	}
	return 0;
}

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

typedef pair<int, int> Data;
typedef pair<int, Data> Pair;

int n;
int m;
Pair ps[114514];
bool infected[114514];

int main() {
  while (1) {
    scanf("%d%d", &n, &m);
    if (n == 0 && m == 0) return 0; 

    fill(infected, infected+n+1, false);
    for (int i=0; i<m; i++) {
      int t, s, d;
      scanf("%d%d%d", &t, &s, &d);
      ps[i] = Pair(t, Data(s, d));
    }

    sort(ps, ps+m);

    infected[1] = true;
    int ans = 1;
    for (int i=0; i<m; i++) {
      Pair pa = ps[i];
      Data d = pa.second;
      int s = d.first;
      int t = d.second;

      if (infected[s] && !infected[t]) {
        infected[t] = true;
        ans++;
      }
    }

    printf("%d\n", ans);
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for(int i=0;i<(n);++i)
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define RREP(i, n) for(int i=(int)(n)-1;i>=0;--i)
#define RFOR(i, a, b) for(int i=(int)(b)-1;i>=(a);--i)
#define ALL(a) a.begin(),a.end()
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl
#define DEBUG(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<< endl;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;
template <typename T1, typename T2>
bool chmax(T1 &a, const T2 &b) {
    if (a < b) { a = b; return true; }
    return false;
}
template <typename T1, typename T2>
bool chmin(T1 &a, const T2 &b) {
    if (a > b) { a = b; return true; }
    return false;
}
template<typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
    os << "{";
    int a = 0;
    for (auto &tp : mp) {
        if (a) os << ", "; a = 1;
        os << tp;
    }
    return os << "}";
}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
    os << p.first << ":" << p.second;
    return os;
}


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    for (;;) {
        int n, m; cin >> n >> m;
        if (n == 0) break;
        vi t(m), s(m), d(m);
        REP(i, m) {
            cin >> t[i] >> s[i] >> d[i];
            --s[i], --d[i];
        }
        vi ord(m); iota(ALL(ord),0);
        sort(ALL(ord), [&](int i,int j){return t[i] < t[j];});

        vi infected(n);
        infected[0] = 1;
        for (int id : ord) {
            infected[d[id]] |= infected[s[id]];
        }

        cout << accumulate(ALL(infected), 0) << endl;
    }

    return 0;
}