Read A Text File And Add The Number

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;
namespace read_a_file {
    class Program {
        static void Main(string[] args) {
            string[] text = System.IO.File.ReadAllLines(@ "C:\Users\350153\Desktop\New folder\input.txt");
            int[] var1 = new int[10];
            int sum = 0;
            //string result = Regex.Replace(var1, @"[^\d]", "");
            foreach(string line in text) {
                string s1 = line;
                int a;
                a = Int32.Parse(s1);
                sum = sum + a;
                Console.WriteLine(s1);
            }
            System.Console.WriteLine(sum);
            //System.Console.WriteLine("{0}", text);
            System.Console.ReadKey();
            FileStream fs = new FileStream("C:\\Users\\350153\\Desktop\\New folder\\output.txt", FileMode.Create);
            TextWriter tmp = Console.Out;
            StreamWriter sw = new StreamWriter(fs);
            Console.SetOut(sw);
            string value = System.IO.File.ReadAllText(@ "C:\Users\350153\Desktop\New folder\input.txt");
            System.Console.WriteLine("{0}", value);
            System.Console.WriteLine("sum of two numbers is " + sum);
            Console.SetOut(tmp);
            sw.Close();
            Console.WriteLine("press a key.....");
            Console.ReadKey();
        }
    }
}