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 Pascal (FPC 3.0.4) (judge verdict: Accepted)

var x,n,i:longint;
a:array[1..100]of longint;
function f(t:longint):Boolean;
var j,c:longint;
begin
c:=0;
for j:=1 to n do if a[j]=t then inc(c);
f:=c=0;
end;
begin
read(x,n);
for i:=1 to n do read(a[i]);
for i:=0 to 111 do begin
if f(x-i)then begin
writeln(x-i);
exit;
end;
if f(x+i)then begin
writeln(x+i);
exit;
end;
end;
end.