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 PyPy3 (7.3.0) (judge verdict: Wrong Answer)

x,n=list(map(int,input().split(' ')))

if n == 0:
    print (x)
else:
    p=list(map(int,input().split(' ')))

    chk_x = False
    pmax = 0
    pmin = 101
    for pr in p:
        if pmax < pr:
            pmax = pr
        if pmin > pr:
            pmin = pr
        if pr == x:
            chk_x = True

    all_i = list(range(0,102))
    target_i = list(set(all_i)^set(p))

    minsub = abs(target_i[0] - x)
    ans = -1
    for i in target_i:
        if abs(i-x) < minsub:
            minsub = abs(i-x)
            ans = i
    # Xがこの範囲にないが最小だった場合
    if not chk_x:
        print(x)
    else:
        print (ans)