using System;
public class Program
    {
        public static void Main(string[] args)
        {
            int a, b;
            int.TryParse(Console.ReadLine(), out a);
            int.TryParse(Console.ReadLine(), out b);
            Console.WriteLine("{0}", a + b);
        }
    }
//It work perfect on my VisualStudio 2008

Edited by author 13.10.2008 22:24

numbers are located on the same line!
So you should read Data in this way:

string[] nums = Console.ReadLine().Split(' ');
int a = int.Parse(nums[0]);
int b = int.Parse(nums[1]);

Console.WriteLine(a+b);