Running a function in Tkinter

Question

I'm trying to make an GUI that runs a function using Tkinter, I'm assigning the function that I want to run to a button, however when I run the .py the function runs automatically and the button doesn't work. I don't know if I'm doing anything wrong. I have the following code:

# ------ Librerias usadas ------ 
import tkinter as tk 

# ------ BackEnd ------   
def obtain_number(list1,list2):
    len1 = len(list1)
    len2 = len(list2) 
    print(len1,len2)


# ------ FrontEnd ------ 
root = tk.Tk() 
root.title('App')  
root.geometry("500x480")
# root.iconbitmap() # Icono de la aplicacion (direccion donde se encuentra)

# Agregar elementos   

# ---- Seleccionar las marcas ---- 
checked_boxes_marcas = ['1','2','3']

lista_marcas = ['1','2','3']   
lista_marcas.sort()

# create a function to update the list of checked boxes
def update_checked_boxes_marcas(v_cb,v_r):
    if v_cb.get():
        checked_boxes_marcas.append(v_r)
    else:
        checked_boxes_marcas.remove(v_r) 
    # print(checked_boxes_marcas)

column_marcas = 0
inter = 3  
tk.Label(text='Marcas').grid(row=0,column=column_marcas)
for i in lista_marcas: 
    value = tk.BooleanVar(value=1)
    checkbox = tk.Checkbutton(root, text=i, variable=value,
                             command=lambda v_cb=value, v_r=i: update_checked_boxes_marcas(v_cb,v_r))
    checkbox.grid(row=inter, column=column_marcas,sticky='w') 
    inter += 3 


# ---- Seleccionar los medios ---- 
checked_boxes_medios = ['a','b','c'] 
                        
lista_medios = ['a','b','c'] 
lista_medios.sort()  

# create a function to update the list of checked boxes
def update_checked_boxes_medios(v_cb,v_r):
    if v_cb.get():
        checked_boxes_medios.append(v_r)
    else:
        checked_boxes_medios.remove(v_r) 
    # print(checked_boxes_medios)

column_medios = 7
tk.Label(text='Medios').grid(row=0,column=column_medios)
inter = 3
for i in lista_medios: 
    value = tk.BooleanVar(value=1)
    checkbox = tk.Checkbutton(root, text=i, variable=value,
                             command=lambda v_cb=value, v_r=i: update_checked_boxes_medios(v_cb,v_r))
    checkbox.grid(row=inter, column=column_medios,sticky='w') 
    inter += 3 


# ---- Botones de validacion, reinicio y ejecutar ----
buttom_ejecutar = tk.Button(root,text='Ejecutar',command=obtain_number(
    checked_boxes_medios,checked_boxes_marcas
)).grid(row=55,column=18) 

# Correr la aplicacion 
root.mainloop() 

I would like that the GUI runs the function when I click the button and it should change depending on the selected checkboxes. I appreciate the help.