#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using pii = pair<int,int>;
using vll = vector<ll>;
using str = string;
using vstr = vector<string>;

#define PB push_back
#define ALL(x) (x).begin() (x).end()
#define FOR(i,s,f) for(int (i) = (s); i < (f); i++)

using vpll = vector<pair<long long, long long>>;

long long n, m;
bool riesenie(vpll& kostra, vpll& query) {
    vector<long long> parent(n, -1);
    vector<long long> depth(n, 1);

    for (long long i = 0; i < n; i++) parent[i] = i;

    for (auto hrana : kostra) {
        long long a = hrana.first;
        long long b = hrana.second;

        while (parent[a] != a) a = parent[a];
        while (parent[b] != b) b = parent[b];

        if (depth[a] >= depth[b]) {
            parent[b] = a;
            depth[a] = max(depth[a], depth[b] + 1);

            parent[hrana.first] = a;
            parent[hrana.second] = a;
        } else {
            parent[a] = b;
            depth[b] = max(depth[b], depth[a] + 1);

            parent[hrana.first] = b;
            parent[hrana.second] = b;
        }
    }

    for (auto hrana : query) {
        long long a = hrana.first;
        long long b = hrana.second;

        while (parent[a] != a) a = parent[a];
        while (parent[b] != b) b = parent[b];

        parent[hrana.first] = a;
        parent[hrana.second] = b;

        if (a == b) return false;
    }

    return true;
}

int main(){
    cin >> n >> m;

    vector<pair<long long, long long>> hrany_blue;
    vector<pair<long long, long long>> hrany_red;

    for (long long i = 0; i < m; i++)
    {
        long long a, b, farba;
        cin >> a >> b >> farba;

        if (farba) hrany_blue.emplace_back(make_pair(a, b));
        else hrany_red.emplace_back(make_pair(a, b));
    }

    if (riesenie(hrany_blue, hrany_red) && riesenie(hrany_red, hrany_blue)) {
        cout << "YES" << '\n';
    } else {
        cout << "NO" << '\n';
    }
}