#include <bits/stdc++.h>

using namespace std;
#define ld long double
#define ll long long
#define int ll

int n, m;
int A[601010], B[601010], C[601010];


int pred[601010];
int sz[601010];

int find(int v) {
    if (pred[v] == v) return v;
    return pred[v] = find(pred[v]);
}
void make(int v) {
    pred[v] = v;
    sz[v] = 1;
}
bool merge(int a, int b) {
    a = find(a);
    b = find(b);
    if (a == b) 
        return false;

    if (sz[a] < sz[b])
        swap(a, b);
    pred[b] = a;
    sz[a] += sz[b];

    return true;
}
bool same_inside(int a, int b) {
    a = find(a);
    b = find(b);
    return (a == b);
}

int32_t main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    
    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        cin >> A[i] >> B[i] >> C[i];
        A[i]++;
        B[i]++;
    }

    for (int trg = 0; trg <= 1; trg++) {
        for (int i = 1; i <= n; i++) {
            make(i);
        }
        // cout << "====== NEW WAVE" << trg << endl;
        for (int i = 1; i <= m; i++) {
            if (C[i] != trg) continue;
            // cout << "MERGE " << A[i] << " " << B[i] << endl;
            merge(A[i], B[i]);
        }

        for (int i = 1; i <= m; i++) {
            if (C[i] == trg) continue;
            // cout << " is it true for " << A[i] << " " << B[i] << " -- " << same_inside(A[i], B[i]) << '\n';
            if (same_inside(A[i], B[i])) {
                cout << "NO\n";
                return 0;
            }
        }
    }
    
    cout << "YES\n";
    return 0;
}

/*
3 3
0 1 1
0 2 1
1 2 0
*/