#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <array>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <stack>
#include <queue>
#include <bitset>
#include <tuple>
#include <cmath>
#include <complex>
#include <algorithm>
#include <utility>
#include <regex>
#include <cstdint>
#include <numeric>
#include <functional>
#include <cassert>

using namespace std;
using ll = long long;
using ull = unsigned long long;

constexpr ll INF = 1'000'000'000'000'000'000;
namespace utils{
#define ALL(x) begin(x), end(x)
#define rALL(x) rbegin(x), rend(x)
    template<class T, class Compare> using p_queue = priority_queue<T, vector<T>, Compare>;
    template<class T> using min_queue = p_queue<T, greater<T>>;
    template<class T> using max_queue = p_queue<T, less<T>>;

    template<class T> bool min_update(T& X, const T& A){ if(X > A) {X = A; return true;} return false; }
    template<class T> bool max_update(T& X, const T& A){ if(X < A) {X = A; return true;} return false; }
    using V_Set = unordered_set<int>;
    using E_Set = unordered_map<int, V_Set>;

    ll operator"" _64(unsigned long long x){ return ll(x); }
    ull operator"" _64u(unsigned long long x){ return ull(x); }

    template<class T>
    vector<T> make_vector(int n, T t){
        return vector<T>(n, t);
    }
    template<class ...Ts>
    auto make_vector(int n, Ts ... ts){
        return vector<decltype(make_vector(ts...))>(n, make_vector(ts...));
    }

    template<class T>
    ostream& operator<<(ostream& os, const vector<T>& v){
        for (auto &&x : v) { os << x << ' '; } cout << endl; return os ;
    }
}
using namespace utils;

namespace Xelmh_UFF {
    class UFF {
        using Int = int;
        std::vector<Int> parent;
        std::vector<Int> rank;


    public:
        explicit UFF(Int n) : parent(n, -1), rank(n, 0) {}
        Int find(Int x) {
            auto &px = parent[x];
            if (px < 0) {
                return x;
            } else {
                return px = find(px);
            }
        }

        bool unite(Int a, Int b) {
            const auto pa = find(a);
            const auto pb = find(b);
            if (pa == pb) return false;

            if (rank[pa] > rank[pb]) {
                parent[pa] += parent[pb];
                parent[pb] = pa;
            } else {
                parent[pb] += parent[pa];
                parent[pa] = pb;

                if (rank[pa] == rank[pb]) {
                    rank[pb]++;
                }
            }
            return true;
        };

        Int size(Int x) {
            const auto px = find(x);
            return -parent[px];
        }

        bool is_same(Int a, Int b) {
            const auto pa = find(a);
            const auto pb = find(b);
            return pa == pb;
        }

    };
}
using namespace Xelmh_UFF;



class solver{
    istream& is;
    ostream& os;

public:
    solver(istream& I, ostream& O) :is(I), os(O) {}
    void run(){
        ll N, M, Q;
        is >> N >> M >> Q;
        if(!is) return;
        UFF uf1(N);
        vector<int> A, B;
        for (int i = 0; i < Q; ++i) {
            int a, b, c;
            is >> a >> b >>c;
            if(c == 0){
                uf1.unite(a, b);
            }
            else {
                A.push_back(a);
                B.push_back(b);
            }
        } // end i
        V_Set ds;
        for (int i = 0; i < N; ++i) {
            ds.insert(uf1.find(i));
        } // end i
        unordered_map<int, int> mp;
        int s = 0;
        for (auto &&d : ds) {
            M -= uf1.size(d) - 1;
            mp[d] = s++;
        } // end d
        if(M > ds.size() * (ds.size() - 1) / 2ll){
            os << "No\n";
            return;
        }
        UFF uf2(s);
        for (int i = 0; i < A.size(); ++i) {
            auto af = uf1.find(A[i]);
            auto bf = uf1.find(B[i]);
            if(uf1.is_same(af, bf)){ os << "No\n"; return; }
            uf2.unite(mp[af], mp[bf]);
        } // end i
        ds.clear();
        for (auto &&p : mp) {
            int i = p.second;
            ds.insert(uf2.find(i));
        } // end p
        for (auto &&d : ds) {
            M -= uf2.size(d) > 1 ? uf2.size(d) : 0;
        } // end d
        if(M < 0) {
            os << "No\n";
            return;
        }
        os << "Yes\n";

    }
};

int main(int argc, char *argv[]) {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << setprecision(16) << scientific;
#ifdef DEBUG
    string test_cases = "test_D.txt";
    cerr << test_cases << " -->" << endl;
    auto fs = fstream(test_cases, fstream::in);
    int loop = 0;
    while(fs) {
        loop++;
        cout << '#' << loop << "#------\n";
        solver(fs, cout).run();
    }
    if(loop <= 1) {
        cout << "===" << endl;
        while(cin) solver(cin, cout).run();
    }
#else
    solver(cin, cout).run();
#endif
    return 0;
}


Measured memory_bytes: 10892