fun readLargeInt () =
    valOf (TextIO.scanStream (LargeInt.scan StringCvt.DEC) TextIO.stdIn)


val () =
    let
        val a = readLargeInt ()
        val b = readLargeInt ()
        val c = readLargeInt ()
        val d = readLargeInt ()

        val ans = (a mod d) * (b mod d) * (c mod d) mod d
    in
        print (LargeInt.toString ans ^ "\n")
    end