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)

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

kouho = list(range(-200, 200))


for i in range(len(p)):
  if p[i] != x:
    del kouho[kouho.index(p[i])]

kouho_num = kouho.index(x)
right = kouho_num + 1
left = kouho_num - 1

if (x not in p):
  print(x)
elif abs(kouho[right] - kouho[kouho_num]) > abs(kouho[kouho_num] - kouho[left]):
  print(kouho[left])
elif abs(kouho[right] - kouho[kouho_num]) == abs(kouho[kouho_num] - kouho[left]):
  print(kouho[left])
else:
  print(kouho[right])