/* -*- coding: utf-8 -*-
 *
 * 2227.cc:  No.2227 King Kraken's Attack - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int INF = 1 << 30;
const long long LINF = 1LL << 60;

/* typedef */

typedef long long ll;

/* global variables */

ll check(int h, int w, int la, int lb, int ka, int kb, int hp, int vp) {
  int dh = min((ll)hp * la, (ll)h), dv = min((ll)vp * lb, (ll)w);
  return min((ll)hp * ka + (ll)vp * kb + (ll)dh * dv, (ll)h * w);
}

int calcvp(int h, int w, int la, int lb, int ka, int kb, int hp) {
  ll hw = (ll)h * w;
  int vp0 = -1, vp1 = w + 1;
  while (vp0 + 1 < vp1) {
    int vp = (vp0 + vp1) / 2;
    if (check(h, w, la, lb, ka, kb, hp, vp) >= hw) vp1 = vp;
    else vp0 = vp;
  }
  return (vp1 <= w) ? vp1 : INF;
}

/* subroutines */

/* main */

int main() {
  int h, w, la, lb, ka, kb;
  scanf("%d%d%d%d%d%d", &h, &w, &la, &lb, &ka, &kb);
  ll hw = (ll)h * w;

  int mins = INF;
  for (int hp = 0; hp <= h; hp++) {
    //printf("hp=%d, vp=%d\n", hp, calcvp(h, w, la, lb, ka, kb, hp));
    mins = min(mins, calcvp(h, w, la, lb, ka, kb, hp) + hp);
  }

  printf("%d\n", mins);
  return 0;
}