Random does not contain a defintion for Range

Unity says that if i save my script can you help me?

Here is the Script: using UnityEngine; using System.Collections;

public class t1 : MonoBehaviour {

     int message = 0;    
     
         public void Start()
         {
             message = UnityEngine.Range(1,29);
         }
     
         public void OnGUI()
         {
             if(message == 1)
                 guiText.text = "42";
             if(message == 2)
                 guiText.text = "1 byte + 0.5 byte = Monochrome";
             if(message == 3)
                 guiText.text = "This is a random Text";
             if(message == 4)
                 guiText.text = "Play it in less than one second!";
             if(message == 5)
                 guiText.text = "Runs under 2000 fps";
             if(message == 6)
                 guiText.text = "Hello Computer :)";
             if(message == 7)
                 guiText.text = "Is your slave!";
             if(message == 8)
                 guiText.text = "XB-70 Valkyrie!";
             if(message == 9)
                 guiText.text = "I want a A-380.";
             if(message == 10)
                 guiText.text = "Not for under 0.01$";
             if(message == 11)
                 guiText.text = "Hasn't any value.";
             if(message == 12)
                 guiText.text = "I've an E-Mail acount.";
             if(message == 13)
                 guiText.text = "Yellow!!!";
             if(message == 14)
                 guiText.text = "Colder than a Pentium(r) 4.";
             if(message == 15)
                 guiText.text = "Runs maybe on your Computer.";
             if(message == 16)
                 guiText.text = "Needs 5TB of RAM.";
             if(message == 17)
                 guiText.text = "Annoying!";
             if(message == 18)
                 guiText.text = "Short play!";
             if(message == 19)
                 guiText.text = "I hope you like it!";
             if(message == 20)
                 guiText.text = "It's made during Apollo 13!";
             if(message == 21)
                 guiText.text = "26 Different Text's.";
             if(message == 22)
                 guiText.text = "64bit rocks!";
             if(message == 23)
                 guiText.text = "Can speak English.";
             if(message == 24)
                 guiText.text = "Give it all your money!";
             if(message == 25)
                 guiText.text = "Is pointless!";
             if(message == 26)
                 guiText.text = "Has an idea!!!";
             if(message == 27)
                 guiText.text = "Yeah, Bluescreen.";
             if(message == 28)
                 guiText.text = "Hi Mr. Trevor Phillips.";
             if(message == 29)
                 guiText.text = "Runs with oxygen";
         }
 }