double@C[4],@L,@R,d,x;list<double>S{L,R};if(C[3]){if((d=C[2]**2-3*C[1]*C[3])>=0){d**=0.5;rep(s,-1,2)if(L<=(x=(-C[2]+d*s)/(3*C[3]))<=R)S.push_back(x);}}else if(C[2]&&L<=(x=-C[1]/C[2]/2)<=R)S.push_back(x);d=4e4;set<ll>s;for(auto&p:S)s.insert((x=C[0]+(C[1]+(C[2]+C[3]*p)*p)*p)>0?2:x?0:1),d<?=abs(x);wt(s.size()<2?d:0);