#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  map<pair<string, string>, int> map_count;
  vector<int> cost_list;
  int n, a, b, k, f;
  string s, t, prv = "";
  cin >> n >> a >> b >> k >> f;
  for (int cost, i = 0; i < n; i++) {
    cin >> s >> t;
    if (s == prv) {
      cost = b;
    } else {
      cost = a;
    }
    prv = t;
    if (s > t) {
      swap(s, t);
    }
    map_count[make_pair(s, t)] += cost;
  }
  for (auto& pkv : map_count) {
    cost_list.push_back(pkv.second);
  }
  sort(cost_list.begin(), cost_list.end(), greater<int>());
  int res = 0;
  for (int i = 0; i < cost_list.size(); i++) {
    if (i < k && cost_list[i] > f) {
      res += f;
    } else {
      res += cost_list[i];
    }
  }
  cout << res;
  return 0;
}
