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: Accepted)

def forbidden_list():
    condition = input()
    num_str = input()
    
    condition_list = condition.split()
    X = int(condition_list[0])
    N = int(condition_list[1])
    
    if N == 0:
        print(X)
        return
    
    num_list_str = num_str.split()
    num_list = []
    for i in num_list_str:
        num_list.append(int(i))
    
    num_list.sort()
    flag = True
    sub = 0
    tmp = X
    
    while flag:
        tmp = X + sub
        for i in num_list:
            count = 0
            if tmp == i:
                count = 1
                break
        if count == 0:
            print(tmp)
            return
        
        sub += 1
        tmp = X - sub
        for i in num_list:
            count = 0
            if tmp == i:
                count = 1
                break
        if count == 0:
            print(tmp)
            return
    
forbidden_list()