local mod = 1000000007
local mfl = math.floor

local function bmul(x, y)
  local x1, y1 = mfl(x / 31623), mfl(y / 31623)
  local x0, y0 = x - x1 * 31623, y - y1 * 31623
  return (x1 * y1 * 14122 + (x1 * y0 + x0 * y1) * 31623 + x0 * y0) % mod
end

local function badd(x, y) return (x + y) % mod end
local n = io.read("*n")
local a = {}
for i = 1, n do
  a[i] = io.read("*n")
end
local b = {a[1]}
for i = 2, n do
  b[i] = bmul(b[i - 1], a[i])
end
local ret = b[n]
local mul = 2
for i = n - 1, 1, -1 do
  ret = badd(ret, bmul(mul, b[i]))
  mul = (mul * 3) % mod
end
print(ret)