# include <bits/stdc++.h>
# define ll long long

using namespace std;

const int N = 2e6 + 5;
int n, m;
ll l, r, a[N], b[N], ans;
int f[N], u[N], v[N];

int find(int x) {
  return f[x] == x ? x : f[x] = find(f[x]);
}

struct E {
  int u, v;
  ll w;
} e[N];

void marge(E e) {
  int x = find(e.u), y = find(e.v);
  if (x != y) {
    f[x] = y;
    ans += e.w;
  }
}

ll sov(ll k) {
  ans = 0;
  for (int i = 1; i <= n; i++) {
    f[i] = i;
  }
  for (int i = 1; i <= m; i++) {
    e[i] = {u[i], v[i], a[i] + b[i] * k};
  }
  sort(e + 1, e + 1 + m, [](E x, E y){return x.w < y.w;});
  for (int i = 1; i <= m; i++) {
    marge(e[i]);
  }
  return ans;
}

int main() {
  // freopen("in.txt", "r", stdin);
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  while (cin >> n >> m >> l >> r) {
    for (int i = 1; i <= m; i++) {
      cin >> u[i] >> v[i] >> a[i] >> b[i];
    }
    cout << min(sov(l), sov(r)) << '\n';
  }
}