Alphabet Frequency

Given a string, compute the frequency of each alphabetical character, ignoring case and non-alphabetic characters. The frequency of each letter should be output in ascending lexicographical order (i.e., from \(a\) to \(z\)).

Each output line must contain one lowercase letter and its corresponding frequency, separated by a single space. If no alphabetic characters are present, nothing should be printed.

inputFormat

The input consists of a single string read from standard input (stdin). The string may include spaces, punctuation, digits, and newline characters.

outputFormat

The output should be a series of lines. Each line must contain a lowercase alphabetical character and its frequency, separated by a space. The letters must appear in ascending alphabetical order. If there are no alphabetic characters, output nothing.

Hello, World!

d 1
e 1
h 1
l 3
o 2
r 1
w 1