/* Topcoder TCO 2017 Q1B 250-Pointer
 * James S. Plank
 * Mon Apr 10 22:27:22 EDT 2017
 */

#include <string>
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

class WaterAndOxygen {
  public:
    double maxDays(int remainH20, int remainO2, int costH2O, int costO2);
};

double WaterAndOxygen::maxDays(int remainH20, int remainO2, int costH2O, int costO2)
{
  double Y, W, X, Z, B, A, Days_W, Days_O;

  W = remainH20;
  X = remainO2;
  Y = costH2O;
  Z = costO2;

  /* Do the algebra to calculate A which makes the 
     number of days that you live on water equal 
     the number of days you live on oxygen. */

  B = W / Y - X / Z;
  A = B * ( 2.0 * Z * Y ) / ( Y + 2.0 * Z );
  
  /* Make A legal. */

  if (A > W) A = W;
  if (A < 0) A = 0;

  /* Now, from A, calculate the number of days you live on water,
     and the number of days you live on oxygen, and return the minimum. */

  Days_W = (W - A) / Y;
  Days_O = (X + A/2.0) / Z;
  return (Days_O < Days_W) ? Days_O : Days_W;
}