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

ans = 0
cnt = 0
D = [0] * N
for i in range(N):
    if A[i] == (i % 2):
        if A[i]:
            D[i] = 1
        else:
            if D[i - 1]:
                D[i] = 1
D[-1] = 0
for i in range(N):
    if D[i]:
        cnt += 1
    else:
        if cnt % 2:
            ans += ((cnt + 1)//2) ** 2
        else:
            ans += cnt//2 * (cnt//2 + 1)
        cnt = 0
if cnt % 2:
    ans += (cnt + 1)//2 ** 2
else:
    ans += cnt//2 * (cnt//2 + 1)

cnt = 0
D = [0] * N
for i in range(N):
    if A[i] == 1 - (i % 2):
        if A[i]:
            D[i] = 1
        else:
            if D[i - 1]:
                D[i] = 1
D[-1] = 0
for i in range(N):
    if D[i]:
        cnt += 1
    else:
        if cnt % 2:
            ans += ((cnt + 1)//2) ** 2
        else:
            ans += cnt//2 * (cnt//2 + 1)
        cnt = 0
if cnt % 2:
    ans += ((cnt + 1)//2) ** 2
else:
    ans += cnt//2 * (cnt//2 + 1)

print(ans)