#include<bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}

struct UnionFind {
  vector< int > data;

  UnionFind(int sz) {
    data.assign(sz, -1);
  }

  bool unite(int x, int y) {
    x = find(x), y = find(y);
    if(x == y) return (false);
    if(data[x] > data[y]) swap(x, y);
    data[x] += data[y];
    data[y] = x;
    return (true);
  }

  int find(int k) {
    if(data[k] < 0) return (k);
    return (data[k] = find(data[k]));
  }

  int size(int k) {
    return (-data[find(k)]);
  }
};


int main() {
  int64 N, M, Q;
  cin >> N >> M >> Q;
  UnionFind uf(N);
  vector< int > A(Q), B(Q), C(Q);
  for(int i = 0; i < Q; i++) {
    cin >> A[i] >> B[i] >> C[i];
  }

  int used = 0;
  for(int i = 0; i < Q; i++) {
    if(C[i] == 0) if(uf.unite(A[i], B[i])) ++used;
  }


  auto Yes = []() {
    cout << "Yes" << endl;
    exit(0);
  };
  auto No = []() {
    cout << "No" << endl;
    exit(0);
  };

  for(int i = 0; i < Q; i++) {
    if(C[i] == 1) {
      if(uf.find(A[i]) == uf.find(B[i])) No();
    }
  }

  vector< int > rot;
  for(int i = 0; i < N; i++) {
    if(uf.find(i) == i) rot.emplace_back(i);
  }


  if(rot.size() == 1) {
    if(used == M) Yes();
    else No();
  } else if(rot.size() == 2) {

    for(int i = 0; i < Q; i++) {
      if(C[i] == 1) No();
    }
    ++used;
    if(used == M) Yes();
    else No();
  } else {
    int64 low = used, high = used;

    bool exist = false;
    for(int i = 0; i < Q; i++) {
      if(C[i] == 1) exist = true;
    }

    int64 v = rot.size();
    high += v * (v - 1) / 2;
    low += rot.size() - 1;
    low += exist;

    if(low <= M && M <= high) Yes();
    else No();
  }
}


Measured memory_bytes: 2428