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 C (GCC 9.2.1) (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>

int main(void)
{
	int a, b, ab=1000,temp, ans,sum, n, x;
	int p[105];
	char s[4], t[20];
	scanf("%d %d", &x, &n);
		
	for (int i = 0;i < 102;i++)
		p[i] = i;

	for (int i = 0;i < n;i++) {
		scanf("%d", &a);
		p[a] = 1000;
	}

	ab = abs(x+1);
	ans = -1;

	for (int i = 0;i < 102;i++) {
		temp = abs(x-p[i]);
		if (temp < ab) {
			ans = p[i];
			ab = temp;
		}

	}


	printf("%d",ans);

	return 0;
}