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 (Clang 10.0.0) (judge verdict: Wrong Answer)

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

int main(void) {
	int x, n;
	int p[101] = { 0 };
	int result = 0;

	scanf("%d", &x);
	scanf("%d", &n);

	for (int i = 0; i < n; i++) {
		int a = 0;
		scanf("%d", &a);
		p[a] = 1;
	}

	int dif = 200;
	int num = 200;
	for (int i = 0; i <= 101; i++) {
		if (p[i] == 0) {
			if (abs(x - i) == dif) {
				if (i < num) {
					num = i;
				}
			}
			else if (abs(x - i) < dif) {
				dif = abs(x - i);
				num = i;
			}
		}
	}

	printf("%d", num);

	return 0;
}