#include<bits/stdc++.h>

using namespace std;

using int64 = long long;

const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;

const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for (int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for (T &in: v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for (auto &e: t) fill_v(e, v);
}

template< typename F >
struct FixPoint: F {
  explicit FixPoint(F &&f): F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}

int main() {
  int64 T, X, A, Y, B;
  cin >> T >> X >> A >> Y >> B;
  int64 ret = infll;
  for(int64 add = 0; add <= 10000000; add++) {
    int64 pos = A * add;
    if(pos <= T) {
      for(int64 sub : {0}) {
        if(sub < 0) continue;
        int64 new_pos = pos - B * sub;
        if(new_pos > T) continue;
        chmin(ret, X * add + Y * sub + T - new_pos);
      }
    } else {
      int64 d = (pos - T) / B;
      for(int64 sub : {d - 3, d - 2, d - 1, d, d + 1, d + 2, d + 3}) {
        if(sub < 0) continue;
        int64 new_pos = pos - B * sub;
        if(new_pos > T) continue;
        chmin(ret, X * add + Y * sub + T - new_pos);
      }
    }
  }
  for(int64 sub = 0; sub <= 10000000; sub++) {
    int64 pos = -B * sub;
    if(pos > T) {
      continue;
    }
    int64 d = (T - pos) / A;
    for(int64 add : {d, d + 1, d + 2}) {
      int64 new_pos = pos + A * add;
      if(new_pos > T) continue;
      chmin(ret, X * add + Y * sub + T - new_pos);
    }
  }
  cout << ret << endl;
}