local mmi, mma = math.min, math.max
local mfl, mce = math.floor, math.ceil
local c, d = io.read("*n", "*n")
--[[
3/2, 1/2
2/7, 5/7

2/7 + 17/14, 1/2 + 3/14
]]

local function solve(x)
  local crem = c - x * 2 / 7
  local drem = d - x * 1 / 2
  if crem < 0 or drem < 0 then return false end
  local z = crem / (17 / 14) + drem / (3 / 14)
  return x <= z
end

local min, max = 0, 1000000007
for irep = 1, 200 do
  local mid = (min + max) / 2
  if solve(mid) then
    min = mid
  else
    max = mid
  end
end
print(min * 2000)