local mce, mfl, msq, mmi, mma = math.ceil, math.floor, math.sqrt, math.min, math.max

local function getprimes(x)
  local primes = {}
  local allnums = {}
  for i = 1, x do allnums[i] = true end
  for i = 2, x do
    if(allnums[i]) then
      table.insert(primes, i)
      local lim = mfl(x / i)
      for j = 2, lim do
        allnums[j * i] = false
      end
    end
  end
  return primes
end

local function getdivisorparts(x, primes)
  local prime_num = #primes
  local tmp = {}
  local lim = mce(msq(x))
  local primepos = 1
  local dv = primes[primepos]
  while(primepos <= prime_num and dv <= lim) do
    if(x % dv == 0) then
      local asdf = {}
      asdf.p = dv
      asdf.cnt = 1
      x = x / dv
      while(x % dv == 0) do
        x = x / dv
        asdf.cnt = asdf.cnt + 1
      end
      table.insert(tmp, asdf)
      lim = mce(msq(x))
    end
    if(primepos == prime_num) then break end
    primepos = primepos + 1
    dv = primes[primepos]
  end
  if(x ~= 1) then
    local asdf = {}
    asdf.p, asdf.cnt = x, 1
    table.insert(tmp, asdf)
  end
  return tmp
end

local function getdivisor(divisorparts)
  local t = {}
  local pat = 1
  local len = #divisorparts
  local allpat = 1
  for i = 1, len do
    allpat = allpat * (1 + divisorparts[i].cnt)
  end
  for t_i_pat = 0, allpat - 1 do
    local div = allpat
    local i_pat = t_i_pat
    local ret = 1
    for i = 1, len do
      div = mfl(div / (divisorparts[i].cnt + 1))
      local mul = mfl(i_pat / div)
      i_pat = i_pat % div
      for j = 1, mul do
        ret = ret * divisorparts[i].p
      end
    end
    table.insert(t, ret)
  end
  -- table.sort(t)
  return t
end

local n = io.read("*n")
if n % 2 == 0 then
  n = mfl(n / 2)
end
local primes = getprimes(mce(msq(n)))
local divps = getdivisorparts(n, primes)
local divs = getdivisor(divps)
local ret = 0
for i = 1, #divs do
  ret = ret + divs[i]
end
print(ret)