he counted the rocks in each pile and wrote them in his notebook with their alphabetical assignations beside them : 13 ( m ) -21 ( u ) -25 ( y ) -18-1 ( a ) -5 ( e ) -8 ( h ) -i 5 ( o ) -9 ( i ) he closed the notebook , placed it in his front pocket , and began the climb back up the sandy slope , clawing his way through the steepest part , taking whole clumps of sea grass with him when he slipped and slid .