#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <cstring>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <list>
#include <fstream>
#include <numeric>
using namespace std;
static const double EPS = 1e-8;
static const double PI = 4.0 * atan(1.0);
static const double PI2 = 8.0 * atan(1.0);
typedef long long ll;

struct Log
{
	int t, s, d;
	bool operator<(const Log& rh) const
	{
		return t < rh.t;
	}
};

int main()
{
	for (int N, M; cin >> N >> M && (N || M);){
		vector<int> dp(N + 1);
		dp[1] = true;

		vector<Log> logs;
		for (int i = 0; i < M; ++i){
			Log l;
			cin >> l.t >> l.s >> l.d;
			logs.push_back(l);
		}

		sort(logs.begin(), logs.end());

		for (vector<Log>::iterator it = logs.begin(); it != logs.end(); ++it){
			dp[it->d] |= dp[it->s];
		}

		cout << count(dp.begin(), dp.end(), 1) << endl;
	}
}