/*
*/

//#pragma comment(linker, "/STACK:16777216")
#define _CRT_SECURE_NO_WARNINGS

#include <fstream>
#include <iostream>
#include <string>
#include <complex>
#include <math.h>
#include <set>
#include <vector>
#include <map>
#include <queue>
#include <stdio.h>
#include <stack>
#include <algorithm>
#include <list>
#include <ctime>
#include <memory.h>
#include <assert.h>

#define y0 sdkfaslhagaklsldk
#define y1 aasdfasdfasdf
#define yn askfhwqriuperikldjk
#define j1 assdgsdgasghsf
#define tm sdfjahlfasfh
#define lr asgasgash
#define norm asdfasdgasdgsd

#define eps 1e-9
#define M_PI 3.141592653589793
#define bs 1000000007
#define bsize 512

const int N = 200000;

using namespace std;

int n, m;
vector<int> order;
vector<pair<int, int> > g[N];

int memo[N];
int ans;
int ITER;
int L[N];
int in_queue[N];
int times[N];
int dist[N];

int solve(int v)
{
	++ITER;

	queue<int> qu;

	qu.push(v);
	L[v] = ITER;
	in_queue[v] = 1;
	times[v] = 0;
	dist[v] = 0;

	while (qu.size())
	{
		int v = qu.front();
		times[v]++;
		if (times[v] > n)
		{
			return 1;
		}
		in_queue[v] = 0;
		qu.pop();
		for (int i = 0; i < g[v].size(); i++)
		{
			int to = g[v][i].first;
			int to_cost = g[v][i].second;
			if (memo[to] != -1)
			{
				if (memo[to] == 1)
					return 1;
				continue;
			}
			int cur_dist;
			if (L[to] != ITER)
				cur_dist = 1e9;
			else
				cur_dist = dist[to];
			if (to_cost + dist[v] < cur_dist)
			{
				dist[to] = to_cost + dist[v];
				if (in_queue[to] == 0)
				{
					qu.push(to);
					in_queue[to] = 1;
				}
				cur_dist = to_cost + dist[v];
			}
			L[to] = ITER;
			dist[to] = cur_dist;
		}
	}
	return 0;
}

int main(){
	//freopen("route.in","r",stdin);
	//freopen("route.out","w",stdout);
	//freopen("F:/in.txt", "r", stdin);
	//freopen("F:/output.txt", "w", stdout);
	ios_base::sync_with_stdio(0);
	//cin.tie(0);
	
	cin >> n >> m;
	
	for (int i = 1; i <= m; i++)
	{
		int a, b, c;
		cin >> a >> b >> c;
		g[a].push_back(make_pair(b, c));
	}

	for (int i = 1; i <= n; i++)
	{
		order.push_back(i);
	}

	random_shuffle(order.begin(), order.end());
	
	for (int i = 1; i <= n; i++)
		memo[i] = -1;

	for (int i = 0; i < order.size(); i++)
	{
		int res = solve(order[i]);
		memo[order[i]] = res;
		ans += res;
		//ans+=solve(order[i]);
	}
	
	cout << ans << endl;

	cin.get(); cin.get();
	return 0;
}