N = int(input())
A = input().replace(' ', '')

all = N * (N + 1) // 2

i = N

onecnt = 0
while i > 0:
    o = A.count('1' * i)
    if o > 0:
        onecnt += (i * (i + 1) // 2) * o
        A = A.replace('1' * i, '')
        i = len(A)
    else:
        i -= 1

print(all - onecnt)