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: Wrong Answer)

X,N = map(int, input().split())
A = list(map(int, input().split()))
if N == 0:
    print(X)
else:
    if N == 1:
        if A[0] != X:
            print(X)
        else:
            print(X-1)
    else:
        B = []
        for i in range(N):
            B.append(abs(X-A[i]))
        B.sort()
        t = 0
        for i in range(N-1):
            if (i+1)//2 != B[i]:
                break
            else:
                t = t+1
        if t == N:
            if N%2 == 1:
                print(X-(N+1)//2)
            else:
                k = 0
                for i in range(N):
                    if A[i] == X-(N//2):
                        k = k+1
                if k == 0:
                    print(X-(N//2))
                else:
                    print(X+(N//2))
        else:
            if t%2 == 1:
                print(X-(t+1)//2)
            else:
                k = 0
                for i in range(N):
                    if A[i] == X-(t//2):
                        k = k+1
                if k == 0:
                    print(X-(t//2))
                else:
                    print(X+(t//2))