let e30 = bigint 1e30 
let e16 = bigint 1e16
let abc =
  stdin.ReadLine().Split(' ')
  |> Array.map int
  

let conv (x:bigint)=
    let y = string <| abs x / e30
    let z = string <| (abs x % e30) + e30
    let s = if x < bigint 0 then "-" else ""
    s + y + "." + (z.Substring(1))

let pr (xs:bigint list) =
    printfn "%d" (List.length xs)
    List.sort xs
    |> List.map conv
    |> List.iter (printfn "%s")

let sq (x:bigint) =
  let rec f e y z =
    if abs (x * e30 - e * e) < e16 * e30 then
      e
    elif e * e < x * e30 then
      f ((e+z)/bigint 2) e z
    else
      f ((y+e)/bigint 2) y e
  f (x/bigint 2) (bigint 0) x
     

match abc with
| [|0;0;0|] -> printfn "-1"
| [|0;0;_|] -> printfn "0"
| [|0;b;c|] -> pr [-bigint c * e30 / bigint b]
| [|a;0;0|] -> printfn "0"
| [|a;0;c|] when -bigint c  * bigint a < bigint  0 -> printfn "0"
| [|a;0;c|] -> let e = -bigint c * e30 / bigint a in let ee = sq e in pr [-ee; ee]
| [|a;b;0|] -> pr [bigint 0; -bigint b * e30 /bigint a]
| [|a;b;c|] ->
    let d = bigint b * bigint b - bigint 4 * bigint a * bigint c
    if d < bigint 0 then
      printfn "0"
    elif d = bigint 0 then
      pr [- bigint b * e30 / (bigint 2 * bigint a)]
    else
      let y = (-bigint b * e30 + sq (d *e30)) / (bigint 2 * bigint a)
      let z = (-bigint b * e30 - sq (d * e30)) / (bigint 2 * bigint a)
      pr [y;z]
| _ -> ()