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: Runtime Error)

#include <stdio.h>
#include <stdlib.h>
int main(void){
  int X,N;
  scanf("%d %d", &X, &N);
  int value = 100;
  int p[N], test[value];
  for(int i=0;i<N;i++){
    scanf("%d", &p[i]);
  }

  for(int i=0;i<value;i++){
    test[i]=i+1;
    for(int j=0;j<N;j++){
      if(test[i]==p[j]){
        test[i] = -1;
        break;
      }
    }
  }

  int dist[N], ans, k=0, min=100;
  for(int i=0;i<value;i++){
    if(test[i]==-1){
      dist[i] = 200;
    }else{
      dist[i] = abs(X - test[i]);
    }
    if(dist[i]<min){
      ans = i;
      min = dist[i];
    }
  }
  printf("%d\n", test[ans]);
}