n = int(input())
a = list(map(int, input().split()))
ans = 0
cur = 0
for i in range(n):
    if a[i] == 1:
        cur += 1
    else:
        ans += cur * (cur + 1) // 2
        cur = 0
print(n * (n + 1) // 2 - (ans + cur * (cur + 1) // 2))