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Count Sorted Vowel Strings

Given an integer n, return the number of strings of length n that consist only of vowels (a, e, i, o, u) and are lexicographically sorted.

Given an integer n, return the number of strings of length n that consist only of vowels (a, e, i, o, u) and are lexicographically sorted.

A string s is lexicographically sorted if for all valid i, s[i] is the same as or comes before s[i+1] in the alphabet.

Example 1

Input: n = 1

Output: 5

Explanation: The 5 sorted strings that consist of vowels only are ["a","e","i","o","u"].

Example 2

Input: n = 2

Output: 15

Explanation: The 15 sorted strings that consist of vowels only are ["aa","ae","ai","ao","au","ee","ei","eo","eu","ii","io","iu","oo","ou","uu"]. Note that "ea" is not a valid string since 'e' comes after 'a' in the alphabet.

Example 3

Input: n = 33

Output: 66045

Constraints

  • 1 <= n <= 50

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