def countdown(n):
    while n > 0:
        print(f"Countdown: {n}")
        n -= 1
    print("Blast off!")

def sum_until_negative():
    total = 0
    count = 0
    inputs = [5, 3, 8, -1, 4, 2]
    
    for value in inputs:
        if value < 0:
            break
        total += value
        count += 1
    
    if count > 0:
        average = total / count
        return total, average
    else:
        return 0, 0

print("Countdown from 5:")
countdown(5)

print("\nSum until negative:")
total, avg = sum_until_negative()
print(f"Total: {total}, Average: {avg:.2f}")