#include <algorithm>
#include <array>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <ostream>
#include<complex>
#include <cmath>
#include <iostream>
#include <stack>
#include <fstream>
#include <queue>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <string>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;



int main()
{
    double x,y,a,b;
    double ans;
    cin >> a >> b >> x >> y;
    double n = a/(a+b);
    double m = b/(a+b);
    printf("%f\n",min(x/n,y/m));
    return 0;
}