Please, anyone explain why my code is wrong. I don't find out.

using System;

class URI {

static void Main(string[] args)
{

    int A, B;
    Console.WriteLine("A =");
    A = Convert.ToInt32(Console.ReadLine());
    Console.WriteLine("B =");
    B= Convert.ToInt32(Console.ReadLine());

    int X = A + B;
    Console.WriteLine("X = {0}", X);

}

}