Second Most Frequent Character :
Difficulty Level : Easy
Submissions : 672
Asked In :
Marks :10
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Given a non-empty string, find out the character that has second-highest frequency of occurrence in the string.
If there are no such characters, print -1
If there are multiple such characters, print the lexicographically smallest of them. ( As per their ASCII value)
Input
First line contains a single integer corresponding to integer N. ( Size of string )
Second line contains N-sized string.
Constraints
$$$ 1 \le N \le 1000000 $$$
The characters in the string could be any valid ASCII character.
Output
A single character having the second-highest frequency and lexicographically smallest if there are multiple characters of the same frequency.
Examples
Input
aaaaaa
Output
-1
Input
nkslanfaaboutcec
Output
c
Input
`SgkEBzNnH
Output
-1
