#include <iostream>
#include <bits/stdc++.h>

using namespace std;

int n, k;
long long lc, pc, lm, pm;
long long t, d;
vector <long long> a;
vector <long long> disp;
vector <long long> dispc;
vector <long long> dispm;
vector <long long> needc;
vector <long long> needm;
bool can;

void printv(vector <long long> &v) {
	for(auto u : v) {
		cout << u << " ";
	}

	cout << endl;
}

int main() {
	cin >> n >> k;
	cin >> lc >> pc >> lm >> pm;
	cin >> t >> d;
	a.resize(n);
	for(int i = 0; i < n; i++) {
		cin >> a[i];
	}

	sort(a.begin(), a.end());
	disp.resize(n + 1);
	dispc.resize(n + 1);
	dispm.resize(n + 1);
	needc.resize(n + 1);
	needm.resize(n + 1);

	can = false;

	for(int i = 0; i < n; i++) {
		disp[i + 1] = disp[i];
		disp[i + 1] += min(a[i] - 1, d);

		dispc[i + 1] = dispc[i];
		needc[i + 1] = needc[i];
		if(a[i] < lc) needc[i + 1] += lc - a[i];
		else dispc[i + 1] += min(a[i] - lc, d);

		dispm[i + 1] = dispm[i];
		needm[i + 1] = needm[i];
		if(a[i] < lm) needm[i + 1] += lm - a[i];
		else dispm[i + 1] += min(a[i] - lm, d);
	}

	// printv(a);
	// printv(disp);
	// printv(dispc);
	// printv(dispm);
	// printv(needc);
	// printv(needm);

	long long currmin = LLONG_MAX;
	for(int i = 0; i * k <= n; i++) {
		long long cost = ((long long)i) * pc + ((long long) n - i * k) * pm;
		long long disp_total = disp[i * k - i] - disp[0];
		long long need_total = 0;
		int cntm = n - i * k;
		disp_total += dispm[n - i] - dispm[i * k - i];
		disp_total += dispc[n] - dispc[n - i];
		need_total += needm[n - i] - needm[i * k - i];
		need_total += needc[n] - needc[n - i];
		//cout << "i=" << i << " disp_total=" << disp_total << " need_total=" << need_total << endl;
		if(i && (a[n - i] < lc - d)) continue;
		if(cntm && (a[i * k - i] < lm - d)) continue;

		if(need_total > disp_total) continue;
		can = true;
		cost += need_total * t;
		currmin = min(currmin, cost);
	}

	cout << ((can) ? currmin : -1) << endl; 
	
	return 0;
}