andtrueXXandfalseYfalseiftrueXYXiffalseXYYadd0XXaddsXYsaddXYfirst0XnilfirstsXconsYZconsYfirstXZfromXconsXfromsXand2true0false0if3add200s1first2nil0cons2from1FULL./TRS/nontermin/CSR/Ex15_Luc98.trs