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 n = lltonumber(io.read())
local ret = n
for j = 2, 59 do
  local min, max = 2LL, 1000000007LL
  local tmp = 1LL
  for z = 1, j do
    tmp = tmp * 2LL
  end
  if n < tmp then break end
  while 1LL < max - min do
    local mid = (min + max) / 2LL
    tmp = 1LL
    local f = true
    for z = 1, j do
      -- tmp = tmp * mid
      -- if n < tmp then f = false break end
      if n / mid < tmp then
        f = false break
      end
      tmp = tmp * mid
    end
    if f then
      min = mid
    else
      max = mid
    end
  end
  tmp = 1LL
  for z = 1, j do
    tmp = tmp * min
  end
  local a = min + j + n - tmp
  if a < ret then ret = a end
end
ret = tostring(ret):gsub("LL", "")
print(ret)