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(void){
       int x,n;
       int p[110];
       int temp1,temp2,s,t;
       int i;
       int j,k;
       scanf("%d %d",&x,&n);
       for(i=0;i<n;i++){
              scanf("%d",&p[i]);
       }


       for(i=0;i<52;i++){
              s=1;
              t=1;
              temp1 = x+i;
              for(j=0;j<n;j++){
                     if(p[j] == temp1){
                            s=0;
                            break;
                     }
              }

              temp2 = x-i;
              for(k=0;k<n;k++){
                     if(p[k] == temp2){
                            t=0;
                            break;
                     }
              }

              if(t==1 || s ==1){
                     if(t==1 && s==0){
                            printf("%d",temp2);
                     }
                     else if(t==0 && s==1){
                            printf("%d",temp1);
                     }
                     else{
                            printf("%d",temp2);
                     }

                     break;
              }
       }

       return 0;

}