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

const int MAXN = 300005;

vector<pair<int,int>> adj[MAXN];
vector<int> redc(MAXN, 0), bluec(MAXN, 0);
vector<int> visited(MAXN, -1);


bool dfs(int node, int par, int red, int blue, int iter){
    redc[node] = red;
    bluec[node] = blue;
    visited[node] = iter;
    for(auto &[nxt, col] : adj[node]){
        if(nxt==par) continue;
        if(col==0) blue++;
        else red++;
        if(visited[nxt]!=-1){
            if(visited[nxt]==iter){
                // backltrack mam loop co osm nasiel teraz
                // kontrola
                int cycleR = red-redc[nxt];
                int cycleB = blue-bluec[nxt];
                if(cycleR==0||cycleB==0){
                    return 1;
                }else if(cycleR>=2&&cycleB>=2){
                    // mam aspon 2
                    return 1;
                }else{
                    return 0;
                }
            }else{
                return 1;
            }
        }
        return dfs(nxt, node, red, blue, iter);
    }
}

int main(void){
    int n, m; cin >> n >> m;
    for(int i = 0; i < m; ++i){
        int u, v, c; cin >> u >> v >> c;
        adj[u].push_back({v,c});
        adj[v].push_back({u,c});
    }
    for(int i = 0; i < n ;++i){
        if(visited[i]==-1){
            if(!dfs(i, -1, 0, 0, i)){
                cout << "NO\n";
                return 0;
            }
        }
    }
    cout << "YES\n";
    return 0;

}