fun readInt () =
    valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn)
              

fun printAns [] = ignore ()
  | printAns (h::tl) =
    let
        val hReal = Real.fromInt h
        val area = 3.0 * hReal * hReal * (Math.sqrt 3.0) / 4.0
    in
        (
          print (Real.toString area ^ "\n");
          printAns tl
        )
    end

fun findAns low high m acc =
    if low = high then Int.max(low mod m, acc)
    else
        (
          let
              val nextLow = low + 1
              val nextAcc = Int.max(low mod m, acc)
          in
              findAns nextLow high m nextAcc
          end
        )

val () =
    let
        val a = readInt ()
        val b = readInt ()
        val c = readInt ()
        val d = readInt ()
        val m = readInt ()

        val ans = if m <= (b + d) - (a + c) + 1 then m - 1
                  else findAns (a + c) (b + d) m 0
    in
        print (Int.toString ans ^ "\n")
    end