python crashes when running code

so i was making a gui for a calculator app. ok so when i run the code it opens up python and in my code i added buttons to click on. but when i click on the button in the gui , python crashes for some reason can someone help me?. im writing code in pycharm. pls help me. this is my code:

from tkinter import *
from tkinter import Button
root = Tk()

def num1():
    input("")


root.title("Basic Calculator")
entry = Entry(root, width=50,bg="green", fg="black")
entry.grid()

b1 = Button(root,  text="1", padx=40, pady=20, command=num1)
b2 = Button(root,  text="2", padx=40, pady=20, command=num1)
b3 = Button(root,  text="3", padx=40, pady=20, command=num1)
b4 = Button(root,  text="4", padx=40, pady=20, command=num1)
b5 = Button(root,  text="5", padx=40, pady=20, command=num1)
b6 = Button(root,  text="6", padx=40, pady=20, command=num1)
b7 = Button(root,  text="7", padx=40, pady=20, command=num1)
b8 = Button(root,  text="8", padx=40, pady=20, command=num1)
b9 = Button(root,  text="9", padx=40, pady=20, command=num1)
b0 = Button(root,  text="0", padx=40, pady=20, command=num1)
b_add = Button(root,  text="+", padx=40, pady=20, command=num1)
b_sub = Button(root,  text="-", padx=40, pady=20, command=num1)
b_div = Button(root,  text="/", padx=40, pady=20, command=num1)
b_mul = Button(root,  text="*", padx=40, pady=20, command=num1)
b_cl = Button(root,  text="Clear", padx=40, pady=20, command=num1)
b_equal = Button(root,  text="=", padx=40, pady=20, command=num1)

b1.grid(row=1, column=0)


root.mainloop()