Problem Statement  
In order to cook hamburgers, a chef must fry them 5 minutes on each side. However, the two 5 minute intervals do not have to happen consecutively. panSize indicates how many hamburgers can fit into the given pan, while hamburgers represents the number of hamburgers that need to be fried. Given panSize and hamburgers return the minimum amount of time (in minutes) required to fry all the hamburgers.  
Definition  
 
Constraints  
  panSize is between 1 and 1000 inclusive.  
  hamburgers is between 0 and 1000 inclusive.  
Examples  
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