#include  <bits/stdc++.h>


using namespace std;


void bfs(int v, const vector<vector<int>> & g, vector<int> & comp) {
    if(comp[v]) return;
    comp[v] = v+1;
    queue<int> q;
    q.push(v);
    while(!q.empty()) {
        for(auto a : g[q.front()]) {
            if(!comp[a]) {
                comp[a] = v+1;
                q.push(a); 
            }
        }
        q.pop();
    }
}




int main() {
    int n,m;
    cin>>n>>m;
    vector<vector<int>> g0(n), g1(n);
    while(m--) {
        int u,v,c;
        cin>>u>>v>>c;
        if(c==0) {
            g0[u].push_back(v);
            g0[v].push_back(u);
        } else {
            g1[u].push_back(v);
            g1[v].push_back(u);
        }
    }


    vector<int> comp0(n,0), comp1(n,0);
    for(int i = 0; i<n;i++) {
        bfs(i, g1, comp1);
        bfs(i, g0, comp0);
    }

    bool success = true;

    for(int i = 0; i<n;i++) {
        for(int j : g0[i]) {
            success &= comp1[i] != comp1[j];
        }
    }

    for(int i = 0; i<n;i++) {
        for(int j : g1[i]) {
            success &= comp0[i] != comp0[j];
        }
    }



    cout<<"NO\n\0YES\n" + 4*success;



}