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 Fortran (GNU Fortran 9.2.1) (judge verdict: Accepted)

program main
    implicit none
    integer x, n
    integer, allocatable, dimension(:) :: p
    integer, dimension(102) :: q
    integer i, min, d, a

    read(*,*) x, n
    allocate(p(n))
    read(*,*) p

    do i = 1, 102
        q(i) = i-1
    end do

    do i = 1, n
        q(p(i)+1) = 1000
    end do

    a = 1
    min = 200
    do i = 1, 102
        d = abs(q(i)-x)
        if(d < min) then
            min = d
            a = q(i)
        else if (d == min) then
            if (q(i) < a) then
                a = q(i)
            end if
        end if
    end do


    write(*,*) a

end program