#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;

#define For(i, a, n) for(ll i=a;i<n;i++)
#define vec vector
#define sz(x) (ll)x.size()
#define all(x) begin(x), end(x)


template<typename... Args>
void dbg(Args&&... args){
    ((cerr<<args<<" |"),...);
    cerr<<endl;
}

void solve(){
    ll n,m;
    cin >> n >> m;
    vec<vec<ll>> neighz(n);
    vec<vec<ll>> neigho(n);
    vec<pll> edgez;
    vec<pll> edgeo;
    for(ll i = 0; i < m; i++){
        ll u,v,c;
        cin >> u >> v >> c;
        if(c == 0){
            neighz[u].push_back(v);
            neighz[v].push_back(u);
            edgez.push_back({u,v});
        }else{
            neigho[u].push_back(v);
            neigho[v].push_back(u);
            edgeo.push_back({u,v});
        }
    }
    vec<ll> compz(n,-1);
    vec<ll> compo(n,-1);
    for(ll i = 0; i < n; i++){
        if(compz[i] != -1){
            continue;
        }
        vec<ll> frontier = {i};
        while(!frontier.empty()){
            ll pos = frontier.back();
            frontier.pop_back();
            if(compz[pos] != -1){
                continue;
            }
            compz[pos] = i;
            for(ll j = 0; j < neighz[pos].size(); j++){
                frontier.push_back(neighz[pos][j]);
            }
        }
    }
    for(ll i = 0; i < n; i++){
        if(compo[i] != -1){
            continue;
        }
        vec<ll> frontier = {i};
        while(!frontier.empty()){
            ll pos = frontier.back();
            frontier.pop_back();
            if(compo[pos] != -1){
                continue;
            }
            compo[pos] = i;
            for(ll j = 0; j < neigho[pos].size(); j++){
                frontier.push_back(neigho[pos][j]);
            }
        }
    }
    for(ll i = 0; i < edgez.size(); i++){
        if(compo[edgez[i].first] == compo[edgez[i].second]){
            cout << "NO\n";
            return;
        }
    }
    for(ll i = 0; i < edgeo.size(); i++){
        if(compz[edgeo[i].first] == compz[edgeo[i].second]){
            cout << "NO\n";
            return;
        }
    }
    cout << "YES\n";
}

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

    ll t = 1;//cin>>t;
    while(t--)solve();
}