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<stdlib.h>

typedef long long ll;

int max(int a, int b){
  if(a > b) return a;
  else return b;
}
int min(int a, int b){
  if(a < b) return a;
  else return b;
}

int sort(const void *a ,const void *b){
  return *(int*)a - *(int*)b;
}


int main(){

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

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

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

  int flag;
  int tmp = 200;
  int ans = 200;
  for(int i = 1; i <= 100; ++i){
    flag = 0;
    for(int j = 0; j < n; ++j){
      if( i == p[j] ) flag = 1;
    }
    if(flag == 0){
      if(tmp > abs(x-i)){
        tmp = min(tmp,abs(x-i));
        ans = i;
      }else if(tmp == abs(x-i)){
        if(ans > i) ans = i;
      }
    }
  }


  printf("%d",ans);

  return 0;
}