def insertion_sort(n, a, c):
    for i in range(n):
        flag = 0
        for j in reversed(range(i)):
            if a[j] > a[j + 1]:
                a[j], a[j + 1] = a[j + 1], a[j]
                flag = 1
            else:
                break
        if flag == 1:
            c += 1
    return c


N = int(input())
A = list(map(int, input().split()))
count = 0

print(insertion_sort(N, A, count))