Jack is blessed with a baby and he and his wife want to name their child. Jack is a mathematician and his wife is very superstitious. She wants the baby's name to contain at least one of her ancestors names as a substring. They have decided that the baby's name should be exactly L characters long, and will only consist of lowercase characters. Jack's wife gives Jack a list of N strings, the names of her ancestors. Jack finds all the name possible names for his baby and lists them in alphabetical order. He asks you to choose the Kth (1-based) name in the list as the name for his child.