Minimum Valid Climbing Time

You are given a dataset that records the times users took to reach a certain level of stairs. Your task is to determine the minimum valid time required to reach that level. A valid time is defined as a time that is strictly greater than 0.

Formally, let \(T = \{ t_1, t_2, \dots, t_n \}\) be the list of recorded times. You need to compute the value

\(\min\{t \in T \mid t > 0\}\)

if there exists at least one valid time; otherwise, output -1.

The integer k is provided as part of the input for consistency with the problem statement but will not affect the result.

inputFormat

The input is read from stdin and contains two lines:

• The first line contains two integers n and k, where n is the number of records and k is the target level (unused in computation).
• The second line contains n space-separated integers representing the recorded times.

outputFormat

Output a single integer representing the minimum valid time (a positive integer) from the dataset. If there is no valid time, output -1.

The output should be printed to stdout.

## sample

5 3
7 -3 10 5 5

5

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