Subsets (2) P33748

Statement

thehtml

Write a program that, given a natural number m and n different words s₁, …, s_n, prints all the subsets of m elements that can be made up with the words.

Input

Input consists of two natural numbers m and n, followed by s₁, …, s_n. Assume n > 0 and 0 ≤ m ≤ n.

Output

Print all the subsets of m words that can be made up with s₁, …, s_n.

Information about the checker

You can print in any order both the solutions and the elements inside each solution.

Public test cases

Input

2 5
hola adeu hi hello bye

Output

{hello,bye}
{hi,bye}
{hi,hello}
{adeu,bye}
{adeu,hello}
{adeu,hi}
{hola,bye}
{hola,hello}
{hola,hi}
{hola,adeu}

Information

Author: Salvador Roura
Language: English
Translator: Carlos Molina
Original language: Catalan
Other languages: Catalan
Official solutions: C++ Python Python
User solutions: C++ Python