#include <bits/stdc++.h>
using namespace std;
const int INF = 1000000000;
const long long INFll = 1000000000000000000ll;
const int MOD = 1000000007;
const int SHIFT = 100000;
int n, m, k, st, p, r;
int f[100500];
long long s[100500];
int x[100500];
int y[100500];
long long z[100500];
bool used[100500];
inline int getRoot(int v) {
  if (v == f[v]) return v;
  return f[v] = getRoot(f[v]);
}
inline pair<long long, int> unite(int x, int y, long long z) {
  x = getRoot(x);
  y = getRoot(y);
  if (x != y) {
    st--;
    if (rand() % 2) {
      f[x] = y;
      s[y] += s[x];
      x = y;
    } else {
      f[y] = x;
      s[x] += s[y];
    }
  }
  s[x] += z;
  return make_pair(-s[x], x);
}
int main() {
  ios_base::sync_with_stdio(0);
  srand(time(0));
  cin >> n >> m >> p >> r;
  for (int i = 0; i < m; ++i) {
    cin >> x[i] >> y[i] >> z[i];
    x[i]--;
    y[i]--;
  }
  for (int i = 0; i < n; ++i) f[i] = i;
  st = n;
  for (int i = 0; i < m; ++i) {
    unite(x[i], y[i], z[i]);
  }
  if (st < r) {
    cout << "NO" << endl;
    return 0;
  }
  r = st - r;
  if (r > p) {
    cout << "NO" << endl;
    return 0;
  }
  priority_queue<pair<long long, int> > q;
  long long mx = 0;
  for (int i = 0; i < n; ++i) {
    if (!used[getRoot(i)]) {
      int v = getRoot(i);
      used[v] = 1;
      q.push(make_pair(-s[v], v));
      mx = max(mx, s[v]);
    }
  }
  vector<pair<int, int> > ans;
  while (p > 0 && r > 0) {
    int v1 = q.top().second;
    long long c1 = -q.top().first;
    q.pop();
    int v2 = q.top().second;
    long long c2 = -q.top().first;
    q.pop();
    long long l = min(1000000000ll, c1 + c2 + 1);
    ans.push_back(make_pair(v1 + 1, v2 + 1));
    pair<long long, int> t = unite(v1, v2, l);
    q.push(t);
    mx = max(mx, -t.first);
    r--;
    p--;
  }
  if (mx == 0 && p > 0 || r > 0) {
    cout << "NO" << endl;
    return 0;
  }
  cout << "YES" << endl;
  for (int i = 0; i < n; ++i) {
    if (s[getRoot(i)] > 0) {
      int x = -1;
      int y = -1;
      for (int j = 0; j < n; ++j) {
        if (getRoot(j) == getRoot(i)) {
          if (x == -1) {
            x = j;
          } else {
            y = j;
          }
        }
      }
      for (int i = 0; i < p; ++i) ans.push_back(make_pair(x + 1, y + 1));
      break;
    }
  }
  for (int i = 0; i < ans.size(); ++i) {
    cout << ans[i].first << " " << ans[i].second << endl;
  }
  return 0;
}
