eq00trueeq0sxfalseeqsx0falseeqsxsyeqxyortrueytrueorfalseyyunionemptyhhunionedgexyihedgexyunionihisEmptyemptytrueisEmptyedgexyifalsefromedgexyixtoedgexyiyrestedgexyiirestemptyemptyreachxyihif1eqxyisEmptyieqxfromieqytoixyihif1trueb1b2b3xyihtrueif1falseb1b2b3xyihif2b1b2b3xyihif2trueb2b3xyihfalseif2falseb2b3xyihif3b2b3xyihif3falseb3xyihreachxyrestiedgefromitoihif3trueb3xyihif4b3xyihif4truexyihtrueif4falsexyihorreachxyrestihreachtoiyunionrestihemptyeqsxsyeqxyunionedgexyihunionihreachxyihtoireachxyiheqytoireachxyihfromireachxyiheqxfromireachxyihisEmptyireachxyiheqxyreachxyihif1eqxyisEmptyieqxfromieqytoixyihif1falseb1b2b3xyihif2b1b2b3xyihif2falseb2b3xyihif3b2b3xyihif3falseb3xyihtoiif3falseb3xyihfromiif3falseb3xyihrestiif3falseb3xyihreachxyrestiedgefromitoihif3trueb3xyihif4b3xyihif4falsexyihunionrestihif4falsexyihtoiif4falsexyihreachtoiyunionrestihemptyif4falsexyihrestiif4falsexyihreachxyrestihif4falsexyihorreachxyrestihreachtoiyunionrestihemptytrueif4falsexyihreachtoiyunionrestihemptyreachxyihif1eqxyisEmptyieqxfromieqytoixyihif1falseb1b2b3xyihif2b1b2b3xyihif2falseb2b3xyihif3b2b3xyihif3falseb3xyihreachxyrestiedgefromitoihif3trueb3xyihif4b3xyihif4falsexyihreachxyrestihtrueif4falsexyihorreachxyrestihreachtoiyunionrestihemptyfalseif4falsexyihrestifalseif4falsexyihtoifalseif4falsexyihunionrestihfalseunionedgexyihunionihtrueunion21if3falseb3xyihrestifalseif3falseb3xyihfromifalseif3falseb3xyihtoifalsereachxyiheqxyfalsereachxyihisEmptyifalsereachxyiheqxfromifalsereachxyihfromifalsereachxyiheqytoifalseeqsxsyeqxytrueeq22reachxyihtoifalse