#include <bits/stdc++.h>
using namespace std;
int main(){
  int A, B, C, D, E;
  cin >> A >> B >> C >> D >> E;
  int N = (B - C) * A;
  if (N == 0){
    cout << 0 << endl;
  } else {
    vector<int> X(N);
    X[0] = D;
    for (int i = 1; i < N; i++){
      X[i] = X[i - 1];
      if (i % 10 == 9 && X[i] >= E){
        X[i] -= E;
      }
    }
    int ans = 0;
    for (int i = 0; i < N; i++){
      ans += X[i];
    }
    cout << ans << endl;
  }
}