#include <cstdio>
#include <cstdlib>
#include <utility>
#include <typeinfo>
#include <cmath>
#include <numeric>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#define REP(i,n) for(int i=0;i<n;i++)
typedef long long ll;
using namespace std;
typedef vector<ll> vl;
typedef pair<ll,ll> pll;
typedef vector<pll> vpll;
typedef vector<string> vs;

int main() 
{
	int n,m;
	while(cin>>n>>m&&!(n==0&&m==0))
	{
		pair<int,int> a[20000],b[20000];
		REP(i,m)
		{
			int x,y,z;
			cin>>x>>y>>z;
			y-=1;z-=1;
			a[i] = make_pair(x,y);
			b[i] = make_pair(x,z);
		}
		sort(a,a+m);
		sort(b,b+m);
		
		bool inf[20000]={};
		inf[0]=true;
		
		int ans(1);
		REP(i,m){if(inf[a[i].second]&&!inf[b[i].second]){inf[b[i].second]=true;ans++;}}

		cout<<ans<<endl;
	}
	return 0;
}