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>

int main(){
	int x, n;
    int num;
    int a[100];
    int i, j;
  
  	for (i = 0; i < 100; i++){
    	a[i] = 0;
    }
  	
  	if(scanf("%d", &x) == 1){};
  	if(scanf("%d", &n) == 1){};

    if (n == 0){
        printf("%d", x);
        return 0;
    }
  	for (i = 0; i < n; i++){
    	if(scanf("%d", &num) == 1){};
      	a[(num - 1)] = 1;
    }
  
  	for(i = 0; i < 99; i++){
        if ((x - 1 - i) >= 0){
    		if (a[(x - 1 - i)] == 0){
            	printf("%d", x - i);
        		break;
            }
        }
      	if ((x - 1 + i) < 100){
        	if (a[(x - 1 + i)] == 0){
            	printf("%d", x + i);
        		break;
        	}
        }
    }
    return 0;
}