def bubble_sort(arr):
    n = len(arr)

    count = 0
    for i in range(n):
        flag = True
        for j in range(0, n - i - 1):
            if arr[j] > arr[j + 1]:
                arr[j], arr[j + 1] = arr[j + 1], arr[j]
                flag = False
                count += 1

        if flag:
            break

    return count


s = list('jonmlkihgfedcba')
print(bubble_sort(s))