Fashion Symbols 2

Given a string consisting only of English letters, find the character or characters that appear most frequently. First, print the highest frequency of any character in the string. Then, print all characters with this frequency in the order of their first appearance in the input.

\InputFileA single string consisting of English letters (uppercase and/or lowercase).

\OutputFileFirst, output a single integer — the highest frequency among the characters. Then, output all characters with this frequency in the order of their first appearance, separated by spaces.