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:
  print(x)
  exit()
if n != 0:
  p = sorted(map(int,input().split()))
aa = []
for i in range(1,101):
  if not i in p:
    aa.append(i)
bb = []
if len(aa) == 0:
  if abs(x-(0)) <= abs(x-101):
    print(0)
    exit()
  else:
    print(101)
    exit()
else:
  for A in aa:
    eee = abs(x-A)
    bb.append(eee)

ans = bb.index(min(bb))
if abs(x-(0)) <= min(bb):
  print(0)
  exit()
elif abs(x-101) < min(bb):
  print(101)
  exit()
else:
  print(aa[ans])
  exit()