// OB���h2009 Day2 A : Infected Computer

#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, n){
		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;
	}
}