using System;

public class Program

{

    public static void Main()

    {

         int [] a = { 1, 2,3, -7, 6, 8, -10, 15,4,6,8,9,5};

        Console.WriteLine("Smallest Positive Number missing is : " + GetSmallestPos(a));

    }

    static int GetSmallestPos(int[] a)

    {

         Array.Sort(a);

        int minPosNum =0;

        int minFlag = 0;

        int minMissing =0;

        for (int i=0; i< a.Length; i++)

        {

            if (a[i]>0 && minFlag==0)

            {

                minFlag=1;

                minPosNum = a[i];

            }

            if (minFlag==1)

            {

                if (minPosNum >1)

                {

                    minMissing =1;

                    break;

                }

                else if (i+1 < a.Length && (a[i+1]-a[i] >1))

                {

                    minMissing = a[i]+1;

                    break;

                }

            }

        }

        if (minMissing==0)

        {

            minMissing = a[a.Length-1]+1;

        }

        return minMissing;

    }

}