def calculate_sum(lst): total = 0 for element in lst: total += element return total

def calculate_sum_of_squares(lst): total = 0 for element in lst: total += element**2 return total

def calculate_sum_of_products(lst1, lst2): total = 0 for x, y in zip(lst1, lst2): total += x * y return total

physics_scores = [15, 12, 8, 8, 7, 7, 7, 6, 5, 3] history_scores = [10, 25, 17, 11, 13, 17, 20, 13, 9, 15]

n = len(physics_scores)

sum_x = calculate_sum(physics_scores) sum_y = calculate_sum(history_scores) sum_xy = calculate_sum_of_products(physics_scores, history_scores) sum_x_squared = calculate_sum_of_squares(physics_scores) sum_y_squared = calculate_sum_of_squares(history_scores)

numerator = n * sum_xy - sum_x * sum_y denominator = ((n * sum_x_squared - sum_x**2) * (n * sum_y_squared - sum_y**2))**0.5 correlation_coefficient = numerator / denominator

print(f"{correlation_coefficient:.3f}")