n = int(input())
alst = list(map(int, input().split()))
ans = n * (n + 1) // 2
cnt = 0
for a in alst:
    if a == 1:
        cnt += 1
    else:
        ans -= cnt * (cnt + 1) // 2
        cnt = 0
ans -= cnt * (cnt + 1) // 2
print(ans)