Assets/NewBehaviourScript1.cs(14,26): error CS0117: `UnityEngine.Input' does not contain a definition for `GetkeyDown'

I am new to this and i dont understand what is wrong with my script. Here is my script:

using UnityEngine; using System.Collections;

public class NewBehaviourScript1 : MonoBehaviour {

 void Start () {
 }
 void Update () 
 {
     if(Input.GetkeyDown (KeyCode.R))
     {
         gameObject.renderer.material.color = Color.red;
     }
     if(Input.Get (KeyCode.B))
     {
         gameObject.renderer.material.color = Color.blue;
     }
     if(Input.Getkeydown (KeyCode.Y))
     {
         gameObject.renderer.material.color = Color.yellow;
     }
 }

}