Problem:
Score : 300 points

Problem Statement

Given are an integer X and an integer sequence of length N: p_1, \ldots, p_N.

Among the integers not contained in the sequence p_1, \ldots, p_N (not necessarily positive), find the integer nearest to X, that is, find the integer whose absolute difference with X is the minimum. If there are multiple such integers, report the smallest such integer.

Constraints

1 \leq X \leq 100

0 \leq N \leq 100

1 \leq p_i \leq 100

p_1, \ldots, p_N are all distinct.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

X N
p_1 ... p_N

Output

Print the answer.

Sample Input 1

6 5
4 7 10 6 5

Sample Output 1

8

Among the integers not contained in the sequence 4, 7, 10, 6, 5, the one nearest to 6 is 8.

Sample Input 2

10 5
4 7 10 6 5

Sample Output 2

9

Among the integers not contained in the sequence 4, 7, 10, 6, 5, the ones nearest to 10 are 9 and 11. We should print the smaller one, 9.

Sample Input 3

100 0

Sample Output 3

100

When N = 0, the second line in the input will be empty. Also, as seen here, X itself can be the answer.

Solution in Python (3.8.2) (judge verdict: Time Limit Exceeded)

def main():
    x, n = map(int, input().split())
    p_lst = list(map(int, input().split()))

    if n == 0:
        minimum = x
    else:
        if x not in p_lst:
            minimum = x

        else:
            lst = []
            flag = False

            while True:
                x1 = x
                x2 = x
                x1 += 1
                x2 -= 1

                if x1 not in p_lst:
                    lst.append(x1)
                    flag = True
                if x2 not in p_lst:
                    lst.append(x2)
                    flag = True

                if flag:
                    break

            minimum = min(lst)

    print(minimum)


if __name__ == '__main__':
    main()