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

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

i = 0

onecnt = 0
for i in range(N + 1, 0, -1):
    o = A.count('1' * i)
    if o > 0:
        onecnt += (i * (i + 1) // 2) * o
        A = A.replace('1' * i, '')

print(all - onecnt)