import random, tkMessageBox
from Tkinter import *
window = Tk()
window.geometry()
options = { :5, :5}
s=StringVar()
s.set(1)
def increase():
    s.set(int(s.get())+1)
def rand():
    if tkMessageBox.askyesno(, ):
        s.set(random.randrange(0,5000))
def update(e):
    if not e.char.isdigit():
        tkMessageBox.showerror('Error', 'Invalid input!') 
        return 
e = Entry(text=s)
e.grid(column=0, row=0, **options)
e.bind('<Key>', update)
b1 = Button(text=, command=increase, **options )
b1.grid(column=1, row=0, **options)
b2 = Button(text=, command=rand, **options)
b2.grid(column=2, row=0, **options)
mainloop()