using System;

public class Program

{

    public static void Main()

    {

        int m =53, n=30;

        //Console.WriteLine($"m={m}, n={n}");

        //Intercambio(ref m, ref n);

        //Console.WriteLine($"m={m}, n={n}");

        Console.WriteLine(SumaMN(m,n));

    }

    public static int SumaMN(int m, int n){

        Intercambio (ref m, ref n);

        int suma = 0;

        for(int x=m; x<n; x++){

            suma += x;

        }

        return suma;

    }

    public static void Intercambio(ref int x, ref int y){

        if(x>y){

            int temp = x;

            x=y;

            y=temp;

        }

    }

}