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: Wrong Answer)

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


int p[110];
int min = 200;
int main(){
	int X,N;
	int x[10];
	scanf("%d%d",&X,&N);
	
	int i;
	
	if(N==0){
		printf("%d\n",X);
		return 0;
	}
	
	for(i=0;i<N;i++){
		int a;
		scanf("%d",&a);
		p[a]=1;
	}
	int index=0;
	int check=0;
	for(i=X-1;i>=-10;i--){
		if(p[i]==0){
			//printf("ddddd\n");
			if(abs(X-i)<min){
				
				min = abs(X-i);
				index = i;
				check=1;
				//printf("+++++  %d %d,min:%d+++++\n",i,abs(X-i),min);
			}
			else break;
		}
		if(check)break;
	}
	check=0;
	
	for(i=X+1;i<=110;i++){
		if(p[i]==0){
			//printf("ddddd\n");
			if(abs(X-i)<min){
				min = abs(X-i);
				index = i;
				//printf("+++++  %d %d,min:%d+++++\n",i,abs(X-i),min);
				check=1;
			}
			else break;
		}
		if(check)break;
	}
	
	if(index!=0)printf("%d\n",index);
	else printf("%d\n",X);

	return 0;
}