Most Frequent Characters

Return the k most frequent characters of s as a list of [character, count] pairs, most frequent first. When two characters have the same count, the one that comes first alphabetically goes first.

If s has fewer than k different characters, return all of them.

Examples

Example 1

Input:

top_characters('abracadabra', 2)

Output:

[['a', 5], ['b', 2]]

a appears 5 times and b and r twice each; b is before r.

Example 2

Input:

top_characters('zzyyx', 5)

Output:

[['y', 2], ['z', 2], ['x', 1]]

Only three different characters exist, so all three are returned. y and z tie, so y is first.

Constraints

• 0 <= len(s) <= 3 * 10**5
• 0 <= k <= 100
• s contains only lower-case letters.