u22Marked_u21ackinMarked_ackinsackoutu21YXackin(s(X),s(Y))u21(ackin(s(X),Y),X)u21(ackout(X),Y)u22(ackin(Y,X))ackin(s(X),s(Y))u21(ackin(s(X),Y),X)u21(ackout(X),Y)u22(ackin(Y,X))Marked_ackin(s(X),s(Y))Marked_u21(ackin(s(X),Y),X)Marked_ackin(s(X),s(Y))Marked_ackin(s(X),Y)Marked_u21(ackout(X),Y)Marked_ackin(Y,X)ackin(s(X),s(Y))u21(ackin(s(X),Y),X)u21(ackout(X),Y)u22(ackin(Y,X))Marked_ackin(s(X),s(Y))Marked_u21(ackin(s(X),Y),X)Marked_ackin(s(X),s(Y))Marked_ackin(s(X),Y)Marked_u21(ackout(X),Y)Marked_ackin(Y,X)u2120ackout0s230Marked_ackin20ackin20Marked_u21220u220Marked_ackin(s(X),s(Y))Marked_u21(ackin(s(X),Y),X)Marked_u21(ackout(X),Y)Marked_ackin(Y,X)ackin(s(X),s(Y))u21(ackin(s(X),Y),X)u21(ackout(X),Y)u22(ackin(Y,X))Marked_ackin(s(X),s(Y))Marked_ackin(s(X),Y)ackin(s(X),s(Y))u21(ackin(s(X),Y),X)u21(ackout(X),Y)u22(ackin(Y,X))Marked_ackin(s(X),s(Y))Marked_ackin(s(X),Y)u21220ackout230s230Marked_ackin30ackin20u220