#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(ll i=0;i<ll(n);i++)

int main(){
  ll h,w,la,lb,ka,kb;
  cin>>h>>w>>la>>lb>>ka>>kb;
  ll ans=1e18;
  rep(a,h+1){
    if(a>ans) break;
    ll up=1e9;
    ll dw=-1;
    while(up-dw>1){
      ll md=(up+dw)/2;
      ll tmp=min(h,la*a)*min(w,lb*md)+ka*a+kb*md;
      if(tmp<h*w) dw=md;
      else up=md;
    }
    ans=min(ans,a+up);
  }
  cout<<ans<<endl;
}