1Marked_minusminus+Marked_+0zyxminus(0)0+(x,0)x+(0,y)y+(minus(1),1)0minus(minus(x))x+(x,minus(y))minus(+(minus(x),y))+(x,+(y,z))+(+(x,y),z)+(minus(+(x,1)),1)minus(x)minus(0)0+(x,0)x+(0,y)y+(minus(1),1)0minus(minus(x))x+(x,minus(y))minus(+(minus(x),y))+(x,+(y,z))+(+(x,y),z)+(minus(+(x,1)),1)minus(x)Marked_+(x,minus(y))Marked_minus(+(minus(x),y))Marked_+(x,minus(y))Marked_+(minus(x),y)Marked_+(x,minus(y))Marked_minus(x)Marked_+(x,+(y,z))Marked_+(+(x,y),z)Marked_+(x,+(y,z))Marked_+(x,y)Marked_+(minus(+(x,1)),1)Marked_minus(x)minus(0)0+(x,0)x+(0,y)y+(minus(1),1)0minus(minus(x))x+(x,minus(y))minus(+(minus(x),y))+(x,+(y,z))+(+(x,y),z)+(minus(+(x,1)),1)minus(x)Marked_+(x,minus(y))Marked_+(minus(x),y)Marked_+(x,+(y,z))Marked_+(+(x,y),z)Marked_+(x,+(y,z))Marked_+(x,y)030Marked_+20+3130minus31010