using System;

public class Program

{

    public void Main()

    {

        Console.WriteLine("Hello World");

        Console.WriteLine(this.SumBetweenNumber(30, 60).ToString());

    }

    public int SumBetweenNumber(int no1, int no2) {

        int[] arr={10, 20, 30, 40, 50, 60, 70, 80, 90, 100};

        int startFlag=0;

        int output=0;

        if ((no1<0) || (no2<0)) {

            output=-1;

        }

        else {

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

                if (arr[i]==no1) {

                    startFlag=1;

                }

                if (startFlag==1) {

                    output=output+arr[i];

                }

                if (arr[i]==no2) {

                    break;

                }

            }

        }

        return output;

    }

}