//#pragma GCC target("avx2,avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
//#include <atcoder/all>
//using namespace atcoder;
//using mint = modint998244353;
//using mint = modint1000000007;
#include <bits/stdc++.h>
using namespace std;
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//using i128 = __int128_t;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
constexpr char ln = '\n';
template<class T1, class T2> inline bool chmax(T1 &a, T2 b) {if (a < b) {a = b; return true;} return false;}
template<class T1, class T2> inline bool chmin(T1 &a, T2 b) {if (a > b) {a = b; return true;} return false;}
inline int topbit(int x) {return x == 0 ? -1 : 31-__builtin_clz(x);}
inline int topbit(long long x) {return x == 0 ? -1 : 63-__builtin_clzll(x);}
inline int botbit(int x) {return x == 0 ? 32 : __builtin_ctz(x);}
inline int botbit(long long x) {return x == 0 ? 64 : __builtin_ctzll(x);}
inline int popcount(int x) {return __builtin_popcount(x);}
inline int popcount(long long x) {return __builtin_popcountll(x);}
inline int kthbit(long long x, int k) {return (x>>k)&1;}
inline void print() {cout << "\n";}
template<class T>
inline void print(const vector<T> &v) {
    for (auto itr = v.begin(); itr != v.end(); ++itr) cout << *itr << " ";
    print();
}
template<class T, class... Args>
inline void print(const T &x, const Args &... args) {
    cout << x << " ";
    print(args...);
}
#ifdef MINATO_LOCAL
#define dump(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl;
inline void debug() {cerr << endl;}
template<class T>
inline void debug(const vector<T> &v) {
    for (auto itr = v.begin(); itr != v.end(); ++itr) cerr << *itr << " ";
    debug();
}
template<class T, class... Args>
inline void debug(const T &x, const Args &... args) {
    cerr << x << " ";
    debug(args...);
}
#else
#define dump(x) void(0)
inline void debug() {}
template<class T> inline void debug(const vector<T> &v) {}
template<class T, class... Args> inline void debug(const T &x, const Args &... args) {}
#endif
struct Fast_ios {Fast_ios() {cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20);};} fast_ios;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

struct UnionFind {
    int N;
    vector<int> node;

    UnionFind(){}
    UnionFind(int N) : N(N), node(N,-1) {}

    void init(int x) {
        node.assign(x,-1);
        N = x;
    }

    bool merge(int x, int y) {
        x = root(x); y = root(y);
        if (x == y) return false;
        if (node[x] > node[y]) swap(x,y);
        node[x] += node[y];
        node[y] = x;
        N--;
        return true; 
    }

    bool same(int x, int y) {return root(x) == root(y);}

    int root(int x) {
        if (node[x] < 0) return x;
        return node[x] = root(node[x]);
    }

    int size(int x) {return -node[root(x)];}

    int count() const {return N;}
};

void No() {
    cout << "No" << ln;
    exit(0);
}

int main() {
    ll N,M,Q; cin >> N >> M >> Q;
    vector<int> A(Q),B(Q),C(Q);
    rep(i,Q) cin >> A[i] >> B[i] >> C[i];

    UnionFind uf(N);
    rep(i,Q) {
        if (!C[i]) uf.merge(A[i],B[i]);
    }

    rep(i,Q) {
        if (C[i] and uf.same(A[i],B[i])) No();
    }

    ll MAX = 0;
    set<int> dic;
    ll cnt = 0;
    rep(i,N) if (uf.size(i) >= 2) {
        dic.emplace(uf.root(i));
        cnt++;
    }
    ll S = SZ(dic);
    MAX = cnt - S;
    ll a = N - cnt + S;
    MAX += a*(a-1)/2;
    if (MAX < M) No();

    ll MIN = accumulate(all(C),0)==0 ? N-1 : N;
    if (M < MIN) No();

    cout << "Yes" << ln;
}


Measured memory_bytes: 5792