#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i < (int)(n+1); i++)
#define repn(i,a,b) for (int i = (int)(a) ; i < (int)(b+1); i++)
#define repv(i, n) for (int i = (int)(n-1); i >= 0; i--)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define sz(x) ((int)(x).size())
#define cauto const auto&
#define bit(n) (1LL<<(n))
#define uni(v) v.erase( unique(v.begin(), v.end()), v.end() );
using ll = long long;
using P = pair<int,int>;
using PP = pair<int, P>;
using Graph = vector<vector<int>>;
using mint = modint998244353;
#ifdef LOCAL
    #include <debug.hpp>
    #define debug(...) debug::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
    #define debug(...) (static_cast<void>(0))
#endif

int main(){
    int t;
    cin >> t;
    int x,a;
    cin >> x >> a;
    int y,b;
    cin >> y >> b;
    int ans1 = 0, ans2 = 0;
    if(t < 0){
        ans1 += (abs(t)/b+1)*y;
        ans2 += (abs(t)/b+1)*y;
        t += (abs(t)/b+1)*b;
    }
    debug(t,ans1,ans2);
    ans1 += t/a * x + t%a;
    int kyori = ((t/a+1) * a - t);
    ans2 += (t/a+1) * x;
    if(kyori % b == 0){
        ans2 += kyori/b * y;
    } else{
        ans2 += (kyori/b+1) * y;
        ans2 += (kyori/b+1)*b - kyori;
    }
    cout << min(ans1,ans2) << endl;
    return 0;
}