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: Accepted)

number=list(map(int,input().split()))
x,n=number[0],number[1]
tmp=[]
try:
    tmp=list(map(int,input().split()))
except:
    pass
answer=x
key_m=x
key_p=x
far_p,far_m=0,0
i,j=0,0
far_answer=0
while answer==x:
    key_p=x+i
    while key_p in tmp:
        i+=1
        key_p=x+i
    key_m=x-j
    while key_m in tmp:
        j+=1
        key_m=x-j
    far_m=int(x-key_m)
    far_p=int(key_p-x)
    if far_m==far_p:
        far_answer=far_m
    else:
        far_answer=min(far_p,far_m)

    if far_answer==far_m:
        answer=key_m
        break
    else:
        answer=key_p
print(answer)