A **happy string** is a string that:

- consists only of letters of the set
`['a', 'b', 'c']`

. `s[i] != s[i + 1]`

for all values of`i`

from`1`

to`s.length - 1`

(string is 1-indexed).

For example, strings **"abc", "ac", "b"** and **"abcbabcbcb"** are all happy strings and strings **"aa", "baa"** and **"ababbc"** are not happy strings.

Given two integers `n`

and `k`

, consider a list of all happy strings of length `n`

sorted in lexicographical order.

Return *the kth string* of this list or return an **empty string** if there are less than `k`

happy strings of length `n`

.

**Example 1:**

Input:n = 1, k = 3Output:"c"Explanation:The list ["a", "b", "c"] contains all happy strings of length 1. The third string is "c".

**Example 2:**

Input:n = 1, k = 4Output:""Explanation:There are only 3 happy strings of length 1.

**Example 3:**

Input:n = 3, k = 9Output:"cab"Explanation:There are 12 different happy string of length 3 ["aba", "abc", "aca", "acb", "bab", "bac", "bca", "bcb", "cab", "cac", "cba", "cbc"]. You will find the 9th string = "cab"

**Example 4:**

Input:n = 2, k = 7Output:""

**Example 5:**

Input:n = 10, k = 100Output:"abacbabacb"

**Constraints:**

`1 <= n <= 10`

`1 <= k <= 100`

class Solution {
public String getHappyString(int n, int k) {
}
}