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 Perl (5.26.1) (judge verdict: Runtime Error)

use strict;
my($x,$n)=glob <>;
if($n!=0){
my @p = <>;
my $t;
my $c;
my $a;
my $b;
my $h;
$h=0;
$a = $x-$t;
$b = $x+$t;
for($t=0;$h!=0;$t++){
for($c=0;$c<100;$c++){
if($a==$p[$c]){
$h = $a;$c=$c+100;}elsif($b==$p[$c]){
$h=$b;$c=$c+100;}}}}
print "$h";
}
else{print "$x";}