#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

template <typename T>
ostream& operator<< (ostream& os, const vector<T> & v) {
    os << "[ ";
    for (const T & elem : v) {
        os < elem << " ";
    }
    os << " ]";
    return os;
}

bool dfs(pair<ll, ll> v, ll main_color, vector<vector<pair<ll, ll>>> & pred, vector<bool> & visited_atleast_once, const vector<vector<pair<ll, ll>>> & graph) {
    ll curr_v = v.first;
    ll curr_floor = v.second;
    visited_atleast_once[curr_v] = true;

    bool ret = false;
    for (const pair<ll, ll> & neig : graph[curr_v]) {
        ll neig_vertex = neig.first;
        ll color = neig.second;

        


        if (curr_floor == 0) {
            if (pred[neig_vertex][0] == pair<ll, ll>{curr_v, curr_floor})
                continue; // protoze soused je predchudce

            if (color == main_color && pred[neig_vertex][0] == pair<ll, ll>{-1, -1}) {
                pred[neig_vertex][0] = pair<ll, ll>{curr_v, curr_floor};
                ret |= dfs({neig_vertex, 0}, main_color, pred, visited_atleast_once, graph);
                pred[neig_vertex][0] = pair<ll, ll>{-1, -1};

            } else if (color != main_color) {
                // prechod do druheho patra
                if (pred[neig_vertex][0] != pair<ll, ll>{-1, -1}) {
                    return true;
                }
                
                pred[neig_vertex][1] = pair<ll, ll>{curr_v, curr_floor};
                ret |= dfs({neig_vertex, 1}, main_color, pred, visited_atleast_once, graph);
                pred[neig_vertex][1] = pair<ll, ll>{-1, -1};
            }


        } else {
            // curr_floor == 1

            if (color != main_color)
                continue; // protoze muzu pouzivat jen main hrany

            if (pred[neig_vertex][1] == pair<ll, ll>{curr_v, curr_floor})
                continue; // protoze soused je predchudce

            if (pred[neig_vertex][0] != pair<ll, ll>{-1, -1}) {
                return true;
            }
            
            if (pred[neig_vertex][1] == pair<ll, ll>{-1, -1}) {
                pred[neig_vertex][1] = pair<ll, ll>{curr_v, curr_floor};
                ret |= dfs({neig_vertex, 1}, main_color, pred, visited_atleast_once, graph);
                pred[neig_vertex][1] = pair<ll, ll>{-1, -1};
            }
            // pred[neig_vertex][1] = pair<ll, ll>{-1, -1}                      ###########################################################################################X
                
        }


    }
    return ret;
}

void test_case() {
    ll n, m;
    cin >> n >> m;

    vector<vector<pair<ll, ll>>> graph(n);
    for (ll i = 0; i < m; ++i) {
        ll u, v, c;
        cin >> u >> v >> c;
        graph[u].push_back({v, c});
        graph[v].push_back({u, c});
    }

    // RED - 0
    // BLUE - 1

    vector<vector<pair<ll, ll>>> pred(n, vector<pair<ll, ll>>(2, {-1, -1}));     // pred[v][copy]
    vector<bool> visited_atleast_once(n, false);
    bool has_red_cycle_with_one_blue = false;
    for (ll i = 0; i < n; ++i) {
        if (!visited_atleast_once[i]) {
            visited_atleast_once[i] = true;
            pred[i][0] = pair<ll, ll>{i, 0};
            has_red_cycle_with_one_blue |= dfs({i, 0}, 0, pred, visited_atleast_once, graph);
        }
    }

    pred = vector<vector<pair<ll, ll>>>(n, vector<pair<ll, ll>>(2, {-1, -1}));
    visited_atleast_once = vector<bool>(n, false);
    bool has_blue_cycle_with_one_red = false;
    for (ll i = 0; i < n; ++i) {
        if (!visited_atleast_once[i]) {
            visited_atleast_once[i] = true;
            pred[i][0] = pair<ll, ll>{i, 0};
            has_blue_cycle_with_one_red |= dfs({i, 0}, 1, pred, visited_atleast_once, graph);
        }
    }

    if (has_red_cycle_with_one_blue || has_blue_cycle_with_one_red)
        cout << "NO" << endl;
    else
        cout << "YES" << endl;
}

int main() {
    cin.tie(0);
    cout.tie(0);
    cin.exceptions(ios::failbit);
    ios::sync_with_stdio(false);
    ll t = 1;
    // cin >> t; // potential comment
    while (t--) {
        test_case();
    }
    return 0;
}