#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
const long long L = 1e9;
int n, m, p, r, par[N];
long long size[N];
vector<int> adj[N];
vector<pair<long long, int> > ans;
priority_queue<pair<long long, int> > q;
int find_par(int v) { return par[v] == v ? v : par[v] = find_par(par[v]); }
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> m >> p >> r;
  if (!m && r == n) {
    cout << (p ? "NO" : "YES") << '\n';
    return 0;
  }
  for (int i = 0; i < n; i++) par[i] = i, size[i] = 0;
  for (int i = 0; i < m; i++) {
    int u, v, l;
    cin >> u >> v >> l;
    u = find_par(--u), v = find_par(--v);
    if (u != v) par[u] = v, size[v] += size[u];
    size[v] += l;
  }
  for (int i = 0; i < n; i++)
    if (par[i] == i) q.push(pair<long long, int>(-size[i], i));
  while (p && q.size() > r) {
    p--;
    pair<long long, int> a, b;
    a = q.top(), q.pop();
    b = q.top(), q.pop();
    long long l = min(L, -a.first + -b.first + 1);
    q.push(pair<long long, int>(a.first + b.first - l, a.second));
    ans.push_back(pair<long long, int>(a.second + 1, b.second + 1));
    par[b.second] = a.second;
  }
  if (q.size() != r)
    cout << "NO\n";
  else {
    cout << "YES\n";
    for (int i = 0; i < ans.size(); i++)
      cout << ans[i].first << ' ' << ans[i].second << '\n';
    for (int v = 0; v < n; v++)
      if (par[v] != v) {
        while (p--) cout << v + 1 << ' ' << par[v] + 1 << '\n';
        break;
      }
  }
  return 0;
}
