#include <bits/stdc++.h>
using namespace std;
#define int long long

#define BLUE true
#define RED false

#define barva bool

template<typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << '{';
    os << p.first << ", " << p.second;
    return os << '}';
}

template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << '[';
    for(int i = 0; i < v.size(); i++) {
        if(i)
            os << ", ";
        os << v[i];
    }
    return os << ']';
}

int kde_je_jednicka(int h) {
    int res = 0;
    for(; h; res++, h >>= 1);
    return res;
}

vector<vector<int>> lca;
int lca_size;
vector<int> hloubka;

int lca_lookup(int a, int b) {
    // A JE NIZ!!!@
    if(hloubka[a] < hloubka[b])
        swap(a, b);
    int diff = hloubka[a] - hloubka[b];
    int lca_index = 0;
    for(; diff; lca_index++, diff >>= 1) {
        a = lca[a][lca_index];
    }

    if(a == b)
        return a;
    
    lca_index = lca_size - 1;
    while(true) {
        int a_next = lca[a][lca_index];
        if(lca_index == 0)
            return a_next;
        int b_next = lca[b][lca_index];
        if(a_next == b_next) {
            lca_index--;
            continue;
        }
        a = a_next;
        b = b_next;
    }
}

bool solve() {
    int n, m;
    cin >> n >> m;
    vector<vector<pair<int, barva>>> edges(n);
    for(int i = 0; i < m; i++) {
        int x, y;
        barva b;
        cin >> x >> y >> b;
        //cout << b << endl;
        edges[x].emplace_back(y, b);
        edges[y].emplace_back(x, b);
    }
    //cout << edges << endl;

    vector<bool> visited(n);
    hloubka = vector<int>(n);
    vector<int> parent(n);
    vector<int> reds(n);
    vector<int> blues(n);

    int max_h = 0;

    set<tuple<int, int, barva>> kruznicoidy;

    int first_unvisited = 0;
    while(first_unvisited < n) {
        // TADY ZACINA BFS
        queue<int> q;

        q.push(first_unvisited);
        visited[first_unvisited] = true;
        hloubka[first_unvisited] = 0;
        parent[first_unvisited] = first_unvisited;
        reds[first_unvisited] = 0;
        blues[first_unvisited] = 0;

        while(q.size()) {
            int v = q.front();
            q.pop();

            for(auto [u, b] : edges[v]) {
                if(visited[u]) {
                    if(u != parent[v]) {
                        int x = v, y = u;
                        if(x > y)
                            swap(x, y);
                        kruznicoidy.emplace(x, y, b);
                    }
                }
                else {
                    q.push(u);
                    visited[u] = true;
                    parent[u] = v;
                    int new_h = hloubka[v] + 1;
                    hloubka[u] = new_h;
                    max_h = max(max_h, new_h);

                    blues[u] = blues[v];
                    reds[u] = reds[v];
                    if(b == BLUE)
                        blues[u]++;
                    else
                        reds[u]++;
                }


            }

            while(first_unvisited < n && visited[first_unvisited])
                first_unvisited++;
        }

    }

    //int r, s;
    //r = 0; s = kde_je_jednicka(r); cout << r << ": " << s << endl;
    //r = 1; s = kde_je_jednicka(r); cout << r << ": " << s << endl;
    //r = 2; s = kde_je_jednicka(r); cout << r << ": " << s << endl;
    //r = 3; s = kde_je_jednicka(r); cout << r << ": " << s << endl;
    //r = 4; s = kde_je_jednicka(r); cout << r << ": " << s << endl;

    lca_size = kde_je_jednicka(max_h) + 1;

    lca = vector<vector<int>>(n, vector<int>(lca_size)); // lca lookup

    for(int i = 0; i < n; i++)
        lca[i][0] = parent[i];
    for(int j = 1; j < lca_size; j++)
        for(int i = 0; i < n; i++) {
            lca[i][j] = lca[lca[i][j - 1]][j - 1];
        }

    //cout << "lca: " << lca << endl;

    //cout << "blues: " << blues << endl;
    //cout << "reds: " << reds << endl;

    for(auto [u, v, b] : kruznicoidy) {
        int predek = lca_lookup(u, v);
        int cerveny = reds[u] + reds[v] - 2 * reds[predek] + (b == RED ? 1 : 0);
        int modry = blues[u] + blues[v] - 2 * blues[predek] + (b == BLUE ? 1 : 0);

        //cout << "cerveny: " << cerveny << endl;
        //cout << "modry: " << modry << endl;

        //cout << "kruznicoid " << u << "<->" << v << endl;

        if(cerveny == 1 || modry == 1)
            return false;
    }
    return true;
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t = 1;
    while(t--) {
        if(solve())
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}