#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")

#define int long long
#define ld long double
#define vec vector
#define all(m) (m).begin(), (m).end()
#define forn(i,n) for(int i=0;i<(n);i++)

using namespace std;

typedef pair<int, int> pii;

int mod = 1e9+7;

int fnd(int v, vec<int> &p) {
    if (v == p[v])
        return v;
    return p[v] = fnd(p[v],p);
}

void mrg(int a, int b, vec<int> &p, vec<int> &sz) {
    a = fnd(a, p);
    b = fnd(b, p);
    if (a == b)
        return;
    if (sz[a]>sz[b])
        swap(a, b);
    p[a] = b;
    sz[b] += sz[a];
}

void solve() {
    int n,m;
    cin>>n>>m;
    vec<pii> e1;
    vec<pii> e2;
    forn(i,m) {
        int a,b,c;
        cin>>a>>b>>c;
        if (c)
            e2.push_back(pii(a,b));
        else
            e1.push_back(pii(a,b));
    }

    vec<int> p1(n);
    vec<int> sz1(n,1);
    vec<int> p2(n);
    vec<int> sz2(n,1);

    forn(i,n) {
        p1[i] = i;
        p2[i] = i;
    }
    bool ans = true;
    for (pii e: e1) {
        mrg(e.first,e.second,p1,sz1);
    }
    for (pii e: e2) {
        mrg(e.first,e.second,p2,sz2);
    }
    for (pii e: e1) {
        ans = ans && (fnd(e.first,p2)!=fnd(e.second,p2));
    }
    for (pii e: e2) {
        ans = ans && (fnd(e.first,p1)!=fnd(e.second,p1));
    }
    if (ans)
        cout<<"YES"<<'\n';
    else
        cout<<"NO"<<'\n';

}

signed main() {

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int tt = 1;
    // cin>>tt;
    while (tt--)
        solve();
    return 0;
}