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

int main(){
  ll a,b,n,m;
  cin >> a >> b >> n >> m;
  ll ans=min(a,b);
  if(a==b){
    cout << ans << endl;
  }
  else if(a<b){
    b-=a;
    cout << ans+b/(m+1) << endl;
  }
  else{
    a-=b;
    cout << ans+a/(n+1) << endl;
  }
}