local ffi = require("ffi")
local C = ffi.C
ffi.cdef[[
long long atoll(const char*);
]]

local function lltonumber(str)
  return C.atoll(str)
end


local function getpattern(n, patall, idx)
  local used = {}
  local retary = {}
  local div = patall
  for i = 1, n do used[i] = false end
  for i = n, 1, -1 do
    div = div / (1LL * i)
    local v_idx = idx / div
    idx = idx % div
    local tmp_idx = 0
    for j = 1, n do
      if not used[j] then
        if tmp_idx == v_idx then
          table.insert(retary, j)
          used[j] = true
          break
        else
          tmp_idx = tmp_idx + 1
        end
      end
    end
  end
  return retary
end

local n, len = io.read():match("(%d+) (%d+)")
n = lltonumber(n)
len = tonumber(len)
local tot = 1LL
for i = 2, len do
  tot = tot * i
end
local ary = getpattern(len, tot, n)
-- print(table.concat(ary, " "))
local ainv = {}
for i = 1, len do ainv[i] = 0 end
for i = 1, len do
  ainv[ary[i]] = i
end
-- print(table.concat(ainv, " "))
local used = {}
for i = 1, len do used[i] = false end
local ret = 0LL
for i = 1, len do
  local add = 1LL
  for j = i + 1, len do
    add = add * (j - i)
  end
  for j = 1, ainv[i] - 1 do
    if not used[j] then
      ret = ret + add
    end
  end
  used[ainv[i]] = true
end
ret = tostring(ret):gsub("LL", "")
print(ret)