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: Accepted)

#include <stdio.h>
#include <stdlib.h>

int main(){
    int x, n;
    int min, k, l; 
    
    min = 200;
    l = 100;

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

    int p[n+1];

    for(int i=1; i<n+1; i++){
         scanf("%d", &p[i]);
    }   
    
    
    for(int i=-1; i<=101; i++){

        int f = 0;
        
            for(int j=1; j<n+1; j++){
                if(i == p[j]){
                    f = 1;
                    break;    
                }
            }

            if(f == 0){
                k = abs(i - x);
                if(min > k){
                     min = k;
                     l = i;
                }
            }
        
    }   

    printf("%d\n", l);
    

return 0;

}