using System;

public class Program

{

    public static void Main()

    {

        int [] array = {3,4,5,6,1,2};

        bool result = sumPair(array,9);

        Console.WriteLine(result);

    }

    public static int FindPivot(int[] array)

    {

        for(int i=1; i<array.Length; i++)

        {

            if(array[i-1] > array[i])

                return i;

        }

        return -1;

    }

    public static bool sumPair(int[] array, int sum)

    {

        int pivotIndex = FindPivot(array);

        int high = pivotIndex-1;

        int low = pivotIndex;

        while( low != high)

        {

            int tempSum = array[low] + array[high];

            if(tempSum == sum)

                return true;

            else if(tempSum < sum)

            {

                low = (low+1) % array.Length;

            }

            else

            {

                high = (array.Length + high -1) % array.Length;

            }

        }

        return false;

    }

}