mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

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

    AA = A[:]
    ans = 0
    for i in range(N):
        if i & 1:
            AA[i] ^= 1
    cnt = [0] * N
    for i in range(N-2, -1, -1):
        if AA[i] == 1:
            cnt[i] = cnt[i+1] + 1
        else:
            cnt[i] = 0
    for i in range(N):
        if i & 1 == 0:
            ans += cnt[i]

    AA = A[:]
    for i in range(N):
        if i & 1 == 0:
            AA[i] ^= 1
    cnt = [0] * N
    for i in range(N - 2, -1, -1):
        if AA[i] == 1:
            cnt[i] = cnt[i + 1] + 1
        else:
            cnt[i] = 0
    for i in range(N):
        if i & 1:
            ans += cnt[i]

    print(ans)


if __name__ == '__main__':
    main()