You are given a list of airline ~tickets~ where ~tickets[i] = [from_{i}, to_{i}]~ represent the departure and the arrival airports of one flight. Reconstruct the itinerary in order and return it.
All of the tickets belong to a man who departs from ~"JFK"~, thus, the itinerary must begin with ~"JFK"~. If there are multiple valid itineraries, you should return the itinerary that has the smallest lexical order when read as a single string.
- For example, the itinerary ~["JFK", "LGA"]~ has a smaller lexical order than ~["JFK", "LGB"]~.
You may assume all tickets form at least one valid itinerary. You must use all the tickets once and only once.