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 Julia (1.4.0) (judge verdict: Accepted)

parseInt(x) = parse(Int, x)
parseMap(x::Array{SubString{String},1}) = map(parseInt, x)
#１行に数値一つならparseInt(readline())
#１行に数値複数ならparseMap(split(readline()))を行数分。
# 例：n,k = readline() |> split |> parseMap
#      a = readline() |> split |> parseMap
function main()
  #a = parseInt(readline())
  X,N = parseMap(split(readline()))
  p = parseMap(split(readline()))
  #println("$X,$N,$p")
  All = [i for i in -100:1:200]
  for i in 1:N
    #println(findall(isequal(p[i],All)))
    #println(findall(All .== p[i])[1])
    splice!(All,findall(All .== p[i])[1])
  end
  #println("$All")
  q = All .- X
  q = abs.(q)
  #println("$q")
  #println("AnsLoc:",findall(isequal(minimum(q)),q))
  #println("Ans:",All[findall(isequal(minimum(q)),q)])
  #println(size(All[findall(isequal(minimum(q)),q)]))
  if size(All[findall(isequal(minimum(q)),q)])[1] > 1
    println(minimum(All[findall(isequal(minimum(q)),q)]))
  else
    println(All[findall(isequal(minimum(q)),q)][1])
  end
  #=
      if x0==0 && y0 > 0
        println("Yes")
      elseif y0==0 && x0 > 0
        println("Yes")

      else
        println("No")
      end
  =#
end
main()