New Year come Jaehyun decide read book 2015 unlike year he n book number integer 1 n the weight ith 1 in book wiAs Jaehyuns house large bookshelf keep n book stack vertically when wants read certain book x follow step describe he lift books book x he push book x stack he put lift book change order after read book x put book x stack he decide read book m day in jth 1jm day read book number integer bj 1bjn to read book use process describe paragraph it possible decide reread book timesafter make plan realize total weight book lift m day heavy so decide change order stack book New Year come minimize total weight you assume book stack possible order note book going read certain step is not consider lift step can help