import tkinter as tk

def calculate_digital_root(input_str):
    # Function to calculate the digital root of a string
    while len(input_str) > 1:
        sum_of_digits = sum(int(digit) for digit in input_str)
        input_str = str(sum_of_digits)
    return int(input_str)

def calculate_button_click():
    input_text = input_entry.get()
    try:
        result_label.config(text=f"Digital Root: {calculate_digital_root(input_text)}")
    except ValueError:
        result_label.config(text="Invalid input. Please enter numbers")

# Create the main window
root = tk.Tk()
root.title("Digital Root Calculator")

# Create and configure input entry
input_label = tk.Label(root, text="Enter numbers or letters:")
input_label.pack()
input_entry = tk.Entry(root)
input_entry.pack()

# Create and configure calculate button
calculate_button = tk.Button(root, text="Calculate Digital Root", command=calculate_button_click)
calculate_button.pack()

# Create and configure result label
result_label = tk.Label(root, text="")
result_label.pack()

# Start the GUI event loop
root.mainloop()