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)

s = {i+1 for i in range(-101,101)}
#print(s)
x, n =map(int,input().split())
 
if n == 0:
  print(x)
  exit()
  
il = list(map(int,input().split()))
 
for i in range(n):
  s.discard(il[i])
s = list(s)
s.sort()
#print(s)
 
absmin = 10000000
ans = 0
 
for i in range(len(s)):
  j = abs(x-int(s[i]))
  if j < absmin:
    ans = s[i]
    absmin = j
    if j == 0:
      break
 
print(ans)