#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define endl '\n'
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rep2(i,a,b) for(int i=int(a);i<int(b);i++)
#define pb emplace_back
#define all(x) (x).begin(),(x).end()
int mod=1e9+7;
int mod2=998244353;
const int INF=1e9;

signed main(){
	ll n,m;
	while(1){
		cin>>n>>m;
		if(n==0&&m==0)break;
		vector<tuple<ll,ll,ll> > tsd;
		rep(i,m){
			ll t,s,d;
			cin>>t>>s>>d;
			s--;
			d--;
			tsd.pb(make_tuple(t,s,d));
		}
		sort(all(tsd));
		vector<bool> inf(n,false);
		inf[0]=true;
		rep(i,m){
			int ns=get<1>(tsd[i]);
			int nd=get<2>(tsd[i]);
			if(inf[ns])inf[nd]=true;
		}
		ll ans=0;
		rep(i,n)if(inf[i])ans++;
		cout<<ans<<endl;
	}
}

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