local a, b, c = io.read("*n", "*n", "*n")
if(a + b <= c) then
  if(b == 0) then print("Impossible")
  elseif(a + b + 9 <= c) then print("Impossible")
  else print(a + b + 9 - c) end
else
  local use = a + b - c
  local ret = 0
  while(10 <= use and 10 <= a) do
    use = use - 9
    a = a - 10
    b = b + 1
  end
  if(use <= a) then print(ret + use)
  else
    local rem = use - a
    print(ret + rem * 10 + a)
  end
end