def f(a,b=[a,a],c=[a,a])d,*e=b;g,h=c;a.times{a+=(b.class==Fixnum)?a:b.size<2?f(a,d,c):d<0?f(a,e,[g+1,h]):g>0?f(a,[a,d-1,e],[g-1,h]):h<0?f(a,[d-1,e],c):f(a,b,[a,h-1])};a end