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: Runtime Error)

import copy
import sys
x,n = map(int, input().split())
nums = list(map(int, input().split()))
nums.sort()
if len(nums) == 0:
    print(x)
    sys.exit()
index = nums.index(x)
ind = copy.deepcopy(index)
ans = 0
while True:
    if ind < 0:
        break
    if nums[ind] != x and  nums[ind+1] - nums[ind] > 2:
        ans = nums[ind+1] - 1
        break
    ind -= 1
ind = copy.deepcopy(index)
while True:
    if ind > n-1:
        break
    if nums[ind] != x and  nums[ind] - nums[ind-1] > 2:
        if abs(ans - x) > abs(nums[ind-1] + 1 - x):
            ans = nums[ind-1] + 1
            break
    ind += 1
if index == 0:
    ans = x - 1
if index == n-1:
    if ans != x - 1
    ans = x + 1
print(ans)