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 sys
import math

x, n = map(int, input().split())
if n == 0:
    print(x)
    sys.exit()

p_list = list(map(int, input().split()))

p_list.sort()

for i in range(n):
    if p_list[i] == x:
        j = i
        k = 1
        while j <= n-1:
            if p_list[i-k] != x-k and i != 0:
                print(x-k)
                sys.exit()
            elif p_list[i+k] != x+k and i != n-1:
                print(x+k)
                sys.exit()
            j += 1
            k += 1
    if p_list[i] > x:
        print(x)
        sys.exit()

if p_list[-1] < x:
    print(x)


#sub = min(abs(p_list[j] - x), abs(p_list[j-1] -x))