/* -*- coding: utf-8 -*-
 *
 * 2099.cc:  No.2099 [Cherry Alpha B] Time Machine - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 100;
const long long LINF = 1LL << 62;

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

template <typename T>
T gcd(T m, T n) {  // m >= 0, n >= 0
  if (m < n) swap(m, n);
  while (n > 0) {
    T r = m % n;
    m = n;
    n = r;
  }
  return m;
}

template <typename T>
T lcm(T m, T n) {
  return m * n / gcd<T>(m, n);
}

inline ll forward(ll t, int x, int a) {
  return t / a * x + t % a;
}

/* main */

int main() {
  int t, x, a, y, b;
  scanf("%d%d%d%d%d", &t, &x, &a, &y, &b);

  ll dd = 0;
  if (t < 0) {
    int s = (-t + b - 1) / b * b;
    dd = (ll)s / b * y;
    t += s;
  }

  int c = lcm<ll>(a, b) / b;
  ll mind = LINF;

  for (int i = 0; i < c; i++) {
    ll d = (ll)y * i + forward(t + (ll)b * i, x, a);
    mind = min(mind, d);
  }

  printf("%lld\n", mind + dd);

  return 0;
}