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


val () =
    let
        val x1 = readInt ()
        val y1 = readInt ()
        val x2 = readInt ()
        val y2 = readInt ()
        val x3 = readInt ()

        val ans = if y1 = y2 then "Yes"
                  else "No"
    in
        print (ans ^ "\n")
    end