C#で入力を整数として読み取る方法は?

res = Convert.ToInt32(val);

string val;
val = Console.ReadLine();

int res;
res = Convert.ToInt32(val);

using System;
using System.Collections.Generic;

class Demo {
   static void Main() {
      string val;
      int res;
   
      Console.WriteLine("Input from user: ");
      val = Console.ReadLine();

      // convert to integer
      res = Convert.ToInt32(val);

      // display the line
      Console.WriteLine("Input = {0}", res);
   }
}