Task: Question Decomposition
Input (English): question: what is the lowest cost for a one way ticket from boston to washington 
Output (English): #1 return flights 
#2 return #1 from  boston 
#3 return #2 to washington 
#4 return #3 that  are one way 
#5 return ticket cost of #4 
#6 return #5 that  is  the lowest