first0XnilfirstsXconsYZconsYn__firstXactivateZfromXconsXn__fromn__sXfirstX1X2n__firstX1X2fromXn__fromXsXn__sXactivaten__firstX1X2firstactivateX1activateX2activaten__fromXfromactivateXactivaten__sXsactivateXactivateXXfirstsXconsYZactivateZactivaten__firstX1X2activateX2activaten__firstX1X2activateX1activaten__firstX1X2firstactivateX1activateX2activaten__fromXactivateXactivaten__fromXfromactivateXactivaten__sXactivateXactivaten__sXsactivateXtrueactivaten__fromXactivateXactivaten__firstX1X2activateX2activaten__firstX1X2activateX1activaten__firstX1X2firstactivateX1activateX2firstsXconsYZactivateZactivaten__sXactivateXtrue1activate1110first201820n__from1111n__s1110from1111n__first211820activate1110cons201120s1110nil00first2118200013activaten__firstX1X2activateX2activaten__firstX1X2activateX1activaten__firstX1X2firstactivateX1activateX2firstsXconsYZactivateZactivaten__sXactivateXfirst0XnilfirstsXconsYZconsYn__firstXactivateZfromXconsXn__fromn__sXfirstX1X2n__firstX1X2fromXn__fromXsXn__sXactivaten__firstX1X2firstactivateX1activateX2activaten__fromXfromactivateXactivaten__sXsactivateXactivateXX1activate1210first201220n__from1010n__s11112from1010n__first211120activate1110cons201820s11112nil05first211120005activaten__firstX1X2activateX2activaten__firstX1X2activateX1activaten__firstX1X2firstactivateX1activateX2firstsXconsYZactivateZfirst0XnilfirstsXconsYZconsYn__firstXactivateZfromXconsXn__fromn__sXfirstX1X2n__firstX1X2fromXn__fromXsXn__sXactivaten__firstX1X2firstactivateX1activateX2activaten__fromXfromactivateXactivaten__sXsactivateXactivateXX1activate1410first201420n__from1010n__s18114from1010n__first211122activate1110cons201820s18114nil00first211122006firstsXconsYZactivateZfirst0XnilfirstsXconsYZconsYn__firstXactivateZfromXconsXn__fromn__sXfirstX1X2n__firstX1X2fromXn__fromXsXn__sXactivaten__firstX1X2firstactivateX1activateX2activaten__fromXfromactivateXactivaten__sXsactivateXactivateXXfirstsXconsYZactivateZfalseactivaten__sXsactivateXfalseactivaten__fromXfromactivateXfalse