#include <bits/stdc++.h>

using namespace std;

#define rep(i,a,b) for(int i =a; i <(b); ++i)

int n, m;
vector<bool> visited;
vector<pair<int, int>> edges_black;
vector<pair<int, int>> edges_white;

void dfs(int v, int comp, vector<int> &cmps, const vector<vector<int>> &adj) {
	visited[v] = true;
	cmps[v] = comp;
	for (int u : adj[v]) {
		if (!visited[u]) dfs(u, comp, cmps, adj);
	}
}

void color(vector<int> &cmps, const vector<vector<int>> &adj) {
	int comp = 0;
	visited = vector<bool>(n, false);
	rep(i, 0, n) {
		if (!visited[i]) {
			dfs(i, comp, cmps, adj);
			++comp;
		}
	}
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);
	
	edges_black.clear();
	edges_white.clear();

	cin >> n >> m;		
	vector<vector<int>> adj_black(n, vector<int>());
	vector<vector<int>> adj_white(n, vector<int>());
	rep(i, 0, m) {
		int a,b,c;
		cin >> a >> b >> c;
		if (c == 0) {
			adj_white[a].push_back(b);
			adj_white[b].push_back(a);
			edges_white.push_back({a, b});
		} else {
			adj_black[a].push_back(b);
			adj_black[b].push_back(a);
			edges_black.push_back({a, b});
		}
	}

	vector<int> cmps_white(n, -1);
	vector<int> cmps_black(n, -1);
	color(cmps_white, adj_white);
	color(cmps_black, adj_black);

	for (const auto [a, b] : edges_black) {
		if (cmps_white[a] == cmps_white[b]) {
			cout << "NO\n";
            return 0;
		}
	}

	for (const auto [a, b] : edges_white) {
		if (cmps_black[a] == cmps_black[b]) {
			cout << "NO\n";			
			return 0;
		}
	}

	cout << "YES\n";
    return 0;
}