Problem A. Simple prefix compression ≡

Statement

Many databases store the data in the character fields (and especially indices) using prefix compression. This technique compresses a sequence of strings A₁, ..., A_N by the following method: if there are strings A_i = a_i,1a_i,2...a_i,p and A_{i + 1} = a_i+1,1a_i+1,2...a_i+1,q

such that for some j ≤ min(p, q) a_i,1 = a_i+1,1, a_i,2 = a_i+1,2, ... a_i,j = a_i+1,j, then the second string is stored as [j]a_i+1,j+1a_i+1,j+2... a_i+1,q, where [j] is a single character with code j.

If j = 0, that is, strings do not have any common prefix, then the second string is prefixed with zero byte, and so the total length actually increases.

Input file format

Output file format

Constraints

Sample tests

3
abc
atest
atext

11

2
test
notest

11

Problem B. Second Best ≡

Statement

Given the sequence of integers A₁, A₂, …, A_N, find a number A_s such that there exists exactly one A_m > A_s, and for all k ≠ m A_k ≤ A_s.

Input file format

Output file format

Constraints

Sample tests

3
1 2 3

2

4
3 3 2 3

-1