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)

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

int main(){
    int i, j;
    int x, n;
    int p[100];

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

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

    for(i = 0;i < n;i++){
        for(j = 0;j < n;j++){
            if(p[j] + i == x){
               break;
            }
        }
        if(j == n){
            printf("%d", x - i);
            return 0;
        }

        for(j = 0;j < n;j++){
            if(p[j] - i == x){
               break;
            }
        }
        if(j == n){
            printf("%d", x + i);
            return 0;
        }
    }

    if(n == 0) printf("%d", x);

    return 0;
}