local mmi, mma = math.min, math.max
local mfl, mce = math.floor, math.ceil
local t = io.read("*n")
local x, a = io.read("*n", "*n")
local y, b = io.read("*n", "*n")

local low = -1
local cand = -1
if 0 < t then
  low = mfl(t / a)
  cand = (t - a * low) + x * low
else
  low = -1
  cand = 1000000007*1000000007
end
for i = 1, 10 * 1000 * 1000 do
  local ecceed = a * (low + i) - t
  back_cnt = mce(ecceed / b)
  rem = b * back_cnt - ecceed
  cand = mmi(cand, rem + (i + low) * x + back_cnt * y)
end
cand = tostring(1LL * cand):gsub("LL", "")
print(cand)