// #pragma GCC target("sse,sse2,sse3,ssse3,sse4")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <list>
 
// hloya template v25
  
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#include <bits/stdc++.h>
#include <valarray>
using namespace std;
  
bool dbg = 0;
  
clock_t start_time = clock();
#define current_time fixed<<setprecision(6)<<(ld)(clock()-start_time)/CLOCKS_PER_SEC
  
#define f first
#define s second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
  
#define ll long long
#define ld long double
#define pii pair<int,int>
#define umap unordered_map<int, int>
  
#define files1 freopen("input.txt","r",stdin)
#define files2 freopen("output.txt","w",stdout)
#define files files1;files2
#define fast_io ios_base::sync_with_stdio(0);cin.tie(0)
  
// #define endl '\n'
#define ln(i,n) " \n"[(i) == (n) - 1]
  
void bad(string mes = "Impossible"){cout << mes;exit(0);}
void bad(int mes){cout << mes;exit(0);}
  
template<typename T>
string bin(T x, int st = 2){
    string ans = "";
    while (x > 0){
        ans += char('0' + x % st);
        x /= st;
    }
    reverse(ans.begin(), ans.end());
    return ans.empty() ? "0" : ans;
}
  
template<typename T>
void upmax(T& x, T y) {
    x = max(x, y);
}
  
template<typename T>
void upmin(T& x, T y) {
    x = min(x, y);
}
 
// inline int popcount(int x){
//     int count = 0;
//     __asm__ volatile("POPCNT %1, %0;":"=r"(count):"r"(x):);
//     return count;
// }
  
template<typename T>
T input(){
    T ans = 0, m = 1;
    char c = ' ';
  
    while (!((c >= '0' && c <= '9') || c == '-')) {
        c = getchar();
    }
  
    if (c == '-')
        m = -1, c = getchar();
    while (c >= '0' && c <= '9'){
        ans = ans * 10 + (c - '0'), c = getchar();
    }
    return ans * m;
}
  
template<typename T> void read(T& a) { a = input<T>(); }
template<typename T> void read(T& a, T& b) { read(a), read(b); }
template<typename T> void read(T& a, T& b, T& c) { read(a, b), read(c); }
template<typename T> void read(T& a, T& b, T& c, T& d) { read(a, b), read(c, d); }
  
const int inf = 1e9 + 20;
const short short_inf = 3e4 + 20;
const long double eps = 1e-6;
const int maxn = (int)3e5 + 12;//, base = 1e9 + 7;
const ll llinf = 2e18 + 5;
const double PI = acos(-1.0);
 
const int mod = 1e9 + 7;
  
template<typename T>
T binpow(T n, T s)
{
    if (s <= 0)
        return 1LL;
    if (s % 2 == 0){
        T b = binpow(n, s / 2);
        return ( 1LL * b * b ) % mod;
    } else {
        return (1LL* binpow(n, s - 1) * n) % mod;
    }
}

int us[maxn];
int p[maxn];

int gp(int v) {
    if (v == p[v]) {
        return v;
    }
    return p[v] = gp(p[v]);
}

void unite(int a, int b) {
    a = gp(a), b = gp(b);
    if (a == b) return;

    if (rand() % 2) {
        swap(a, b);
    }

    p[a] = b;
}

ll clique(int n) {
    return 1ll * n * (n - 1) / 2;
}

int main() {
    // files1;
    fast_io;

    int n;
    ll m;
    int q;
    cin >> n >> m >> q;

    for (int i = 0; i < n; i++) {
        p[i] = i;
    }

    vector<pii> bdedg;

    for (int i = 0; i < q; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        if (c == 0) {
            unite(a, b);
        } else {
            bdedg.eb(a, b);
        }
    }

    auto ans = [](bool x) {
        cout << (x ? "Yes" : "No");
        exit(0);
    };

    int cmp = 0;
    for (int i = 0; i < bdedg.size(); i++) {
        int u, v;
        tie(u, v) = bdedg[i];
        if (gp(u) == gp(v)) ans(0);
    }
    for (int i = 0; i < n; i++) {
        if (gp(i) == i) cmp++;
    }

    if (!bdedg.empty()) {
        if (cmp < 2) throw;
        if (cmp == 2) ans(0);
    }

    int const_edges = n - cmp;

    ll mnedg = bdedg.empty() ? cmp - 1 : cmp;
    ll mxedg = clique(cmp);

    mnedg += const_edges;
    mxedg += const_edges;

    ans(m >= mnedg && m <= mxedg);
    return 0;
}


Measured memory_bytes: 1784