A12237 | Diverse Substring

You are given a string $s$ , consisting of $n$ lowercase Latin letters.

A substring of string $s$ is a continuous segment of letters from $s$ . For example, "defor" is a substring of "codeforces" and "fors" is not.

The length of the substring is the number of letters in it.

Let's call some string of length $n$ diverse if and only if there is no letter to appear strictly more than $\frac n 2$ times. For example, strings "abc" and "iltlml" are diverse and strings "aab" and "zz" are not.

Your task is to find any diverse substring of string $s$ or report that there is none. Note that it is not required to maximize or minimize the length of the resulting substring.

The first line contains a single integer $n$ ( $1 \le n \le 1000$ ) — the length of string $s$ .

The second line is the string $s$ , consisting of exactly $n$ lowercase Latin letters.

Print "NO" if there is no diverse substring in the string $s$ .

Otherwise the first line should contain "YES". The second line should contain any diverse substring of string $s$ .