import re
import random

def calculate(expression, num=1):
    """Calculate the result of the expression using n[0], n[1], ..."""

    # Generate random numbers and replace placeholders with them in the expression
    numbers = [random.randint(1, 10) for _ in range(num)]
    new_expression = expression

    for i, num in enumerate(numbers):
        placeholder = f'n[{i}]'
        new_expression = re.sub(rf'\b{n[i]}(\W|$)', str(num), new_expression)

    # Evaluate the result
    return eval(new_expression)

def parse_expression(expression):
    """Parse an algebraic expression and determine the required number of numbers"""

    count_n = 0

    i = 0
    for char in expression:
        if char == 'n' and (i+1 < len(expression) and expression[i+1] == '['):
            count_n += 1
        i += 1

    return count_n

def main():
    expression = input("Enter an algebraic structure (e.g., -(+)): ")

    # Handle the empty string case by providing a default expression
    if not expression:
        expression = '-(+)'

    num_needed = parse_expression(expression)

    result = calculate(expression, num_needed)

    print(f"Generated calculation: {expression}")
    print(f"Result: {result}")

if __name__ == "__main__":
    main()