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()
{
	int a,b,c[100],i,d=0,x=0;
	scanf("%d%d",&a,&b);
	for(i=0;i<b;i++) scanf("%d",&c[i]);
	while(1){
		for(i=0;i<b;i++){
			if(a-d==c[i]){
				x=1;
				break;
			}
		}
		if(x==0){
			printf("%d\n",a-d);
			return 0;
		}
		x=0;
		for(i=0;i<b;i++){
			if(a+d==c[i]){
				x=1;
				break;
			}
		}
		if(x==0){
			printf("%d\n",a+d);
			return 0;
		}
		x=0;
		d++;
	}
	return 0;
}