local mfl = math.floor
local n = io.read("*n")
local t = {0, 0, 0}
for i = 1, n do
  a = math.min(3, io.read("*n"))
  t[a] = t[a] + 1
end
local ret = 0
ret = ret + t[1] * (t[1] - 1)
ret = ret + mfl(t[2] * (t[2] - 1) / 2)
ret = ret + mfl(t[3] * (t[3] - 1) / 2)
ret = ret + t[1] * t[3] * 2
ret = ret + t[2] * t[3]
ret = ret + t[1] * t[2] * 3
print(ret)