Q=gets.to_i Inputs=gets(p).split.map(&:to_r) def read() x,y=Inputs.shift(2) return x+y*1i end x=[read(),read(),read()] def cross(a,b) return a.real*b.imag-a.imag*b.real end def parallel(a,b) return cross(a,b)==0 end o=r=nil if parallel(x[1]-x[0],x[2]-x[0]) maxr=0 x.combination(2).each{|a,b| d=(b-a).abs2 if maxr