n, h, w = map(int, input().split())

lst = []
for i in range(3, -1, -1):
    lst.append((n + i) // 4)

ans = 0
pos = [(1, 1), (h, 1), (1, w), (h, w)]
for i in range(4):
    for j in range(i + 1, 4):
        ans += lst[i] * lst[j] * (abs(pos[i][0] - pos[j][0]) + abs(pos[i][1] - pos[j][1]))
print(ans)