can't add script behaviour the script needs to derive from monobehaviour

I can't find the error why it doesn't let me put the script on an object


using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PantallaRecibeBoton : MonoBehaviour
{
public string TextScreen;
public TextMesh Pantalla;

void Update()
{
Boton boton = GetComponent<Boton>();
TextScreen = boton.texto;

Pantalla = (TextMesh)GameObject.Find("Cargando").GetComponent<TextMesh>();

Pantalla.text = "" + TextScreen;
}
}

 

Is your script file named the same as your class name? (note the caps)

 

When you post code, use [code ]code tags[/code]

You will need to fix all compiler errors in your script before you can attach it. Do you have compiler errors when you open up Unity's console?