--[[
ax + b(cx)
cx + d(ax)

a + bc <= c + da
a(1-d) <= c(1-b)
a/(1-b) <= c/(1-d)
(1-d)/c <= (1-b)/a
]]

local n = io.read("*n")
local a, b = {}, {}
for i = 1, n do a[i] = io.read("*n") end
local t = {}
for i = 1, n do
  t[i] = i
  b[i] = io.read("*n")
end
table.sort(t, function(x, y)
  return (a[y] * (1 - b[x]) < a[x] * (1 - b[y]))
end
)
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 ret = 0
local v = 1
for _i = 1, n do
  local i = t[_i]
  ret = badd(ret, bmul(v, a[i]))
  v = bmul(v, b[i])
end
print(ret)