#include <iostream>	//cin, cout
#include <vector>	//vector
#include <algorithm> //sort,min,max,count
#include <string>	//string,getline, to_string
#include <ios>		//fixed
#include <iomanip>	//setprecision
#include <utility> //swap, pair
#include <cstdlib>	//abs(int)
#include <cmath>	//sqrt,ceil,M_PI, pow, sin
#include <sstream>	//stringstream, getline
#include <numeric>	//gcd, accumlate
#include <deque>	//deque
#include <random>	//randam_device
#include <limits>	//numeric_limits

using namespace std;
int main(void){
    int A, B, C, D, E;
    int candy, cost;
    cin >> A >> B >> C;
    candy = A * (B - C);
//    cout << candy;
    cin >> D >> E;
    cost = D * candy;
    if(candy % 10 != 0){
        cout << cost;
    }
    else if(candy % 10 == 0){
        if(E <= D){
            if (cost - E < 0){
                cout << 0;
            }
            else{
            cout << cost - E;
            }
        }
        else{
            cout << cost;
        }
    }

    return 0;
}