Problem Statement  
You have survived a shipwreck and need to swim to the land. You can swim at a speed of at most V meters per second. The ocean's stream moves you with a constant speed of U meters per second. Imagine a Cartesian system of coordinates in which you are at point (0,0), and the ocean's stream moves in the positive direction of the xaxis. You are given four integers x, y, V and U. Return a double representing the minimum time in seconds in which you can reach point (x, y). If this point can't be reached, return 1.  
Definition  
 
Notes  
  Your return value must have an absolute or relative error less than 1e9.  
Constraints  
  x and y will be between 100 and 100, inclusive.  
  U and V will be between 0 and 100, inclusive.  
Examples  
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