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 <limits.h> 
#include <stdlib.h>

int main(void) {
    int a[100],e[100];int i,o,j;
	for(i=0;i<100;i++){
	    a[i]=i+1;
	}
	int b,c;
	scanf ("%d%d",&b,&c);
	if(c==0){printf("%d",b);return 0;}
	int d[c];
    for(i=0;i<c;i++){
        scanf("%d",&d[i]);
    }
    for(i=0;i<100;i++){
        for(o=0;o<c;o++){
        if (a[i]==d[o]){a[i]=0;}
    }}
    for(i=0;i<100;i++){
        if(a[i]<=b){e[i]=b-a[i];}
        else{e[i]=a[i]-b;}
        }
    for(i=0;i<100;i++){
        for(j=i+1;j<100;j++){
        if(e[i]>e[j]){
            o=e[i];
            e[i]=e[j];
            e[j]=o;
    }}}
    i=e[0]+b;o=b-e[0]-1;
    if(a[o]==0){printf("%d",i);}
    else{printf("%d",o+1);}
    return 0;
}