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>

int main(void)
{
	unsigned long int a, b, c[100];
	int i, j = 0, check = 0;

	scanf("%ld%ld", &a, &b);

	for (i = 0; i < b; i++) {
		scanf("%ld", &c[i]);
	}

	while (1) {
		for (i = 0; i < b; i++) {
			if (a - j == c[i]) {
				check = 1;
				break;
			}
		}
		if (check == 0) {
			printf("%ld", a - j);
			return 0;
		}

		check = 0;

		for (i = 0; i < b; i++) {
			if (a + j == c[i]) {
				check = 1;
				break;
			}
		}
		if (check == 0) {
			printf("%ld", a + j);
			return 0;
		}

		check = 0;

		j++;




	}


	return 0;
}