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 function modpow(src, pow)
  local res = 1
  while 0 < pow do
    if pow % 2 == 1 then
      res = bmul(res, src)
      pow = pow - 1
    end
    src = bmul(src, src)
    pow = mfl(pow / 2)
  end
  return res
end

local function modinv(src)
  return modpow(src, mod - 2)
end

local invs = {1}
local invfact = {1}
for i = 2, 10001 do
  invs[i] = bmul(mfl(mod / i), mod - invs[mod % i])
  invfact[i] = bmul(invfact[i - 1], invs[i])
end
local fact = {1}
for i = 2, 10001 do
  fact[i] = bmul(fact[i - 1], i)
end

local function getComb(n, k)
  if k == 0 or k == n then return 1 end
  return bmul(fact[n], bmul(invfact[k], invfact[n - k]))
end

local function lltonumber(str)
  local ret = 0LL
  for i = 1, #str do
    ret = ret * 10LL + str:sub(i, i):byte() - 48
  end
  return ret
end

local s = io.read()
local tm1 = os.clock()
local n, k = s:match("(%d+) (%d+)")
n = lltonumber(n)
k = tonumber(k)
local b = {1}
for i = 1, k do
  local sum = invfact[i + 1] -- b[1] * invfact[i + 1 - j]
  for j = 1, i - 1 do
    sum = badd(sum, bmul(b[j + 1], bmul(invfact[i + 1 - j], invfact[j])))
    -- sum = badd(sum, bmul(b[j + 1], getComb(i + 1, j)))
  end
  b[i + 1] = mod - bmul(sum, fact[i])
  -- b[i + 1] = mod - bmul(sum, bmul(fact[i + 1], invs[i + 1]))
end
local tm2 = os.clock()
-- print(tm2 - tm1)
if n == 1LL then
  print(1)
else
  local nm = (n + 1LL) % 1000000007LL
  nm = tostring(nm):gsub("LL", "")
  nm = tonumber(nm)
  local sum = 0
  local nmul = nm
  for i = k, 0, -1 do
    local v = bmul(getComb(k + 1, i), bmul(b[i + 1], nmul))
    sum = badd(sum, v)
    nmul = bmul(nmul, nm)
  end
  sum = bmul(sum, invs[k + 1])
  print(sum)
end