andtrueXactivateXandfalseYfalseiftrueXYactivateXiffalseXYactivateYadd0XactivateXaddsXYsn__addactivateXactivateYfirst0XnilfirstsXconsYZconsactivateYn__firstactivateXactivateZfromXconsactivateXn__fromn__sactivateXaddX1X2n__addX1X2firstX1X2n__firstX1X2fromXn__fromXsXn__sXactivaten__addX1X2addactivateX1X2activaten__firstX1X2firstactivateX1activateX2activaten__fromXfromXactivaten__sXsXactivateXXand2true0activate1false0if3add200s1n__add2first2nil0cons2n__first2from1n__from1n__s1FULL./TRS/TRCSR/Ex15_Luc98_FR.trs