def ends_up_at_start(input_text):
    # Step 1: Initialize coordinates and direction by setting the starting point at (0, 0) and face north.
    cur_x, cur_y = 0, 0
    cur_direction = 0

    # Step 2: Identify and list up instructions from the input text.
    instructions = parse_instructions(input_text)
    
    # Step 3: Process each instruction and update the current coordinates and direction. In order to keep track of changes, output the instruction, current and updated coordinates and direction.
    for i, instruction in enumerate(instructions):
        new_x, new_y, new_direction = process_instruction(instruction, cur_x, cur_y, cur_direction) # process instruction to calculate new position and direction
        print(f"Step {i}: {instruction} - current coordinates: ({cur_x}, {cur_y}), current direction: {cur_direction} -> updated coordinates: ({new_x}, {new_y}), updated direction: {new_direction}")
        cur_x, cur_y, cur_direction = new_x, new_y, new_direction

    # Step 4: Return "yes" if the final coordinates are (0, 0). Otherwise, return "no" as the final answer.
    return 'yes' if cur_x == 0 and cur_y == 0 else 'no'