N=gets.to_i
r=Float::INFINITY
t=0
c=[]
N.times{
	a,b=gets.split.map &:to_i
	t+=a
	c<<a+b
}
q1=[]
(1<<N/2).times{|i|
	s=0
	(N/2).times{|j|i[j]>0&&s+=c[j]}
	q1<<s
}
q1=q1.uniq.sort
q2=[]
(1<<(N-N/2)).times{|i|
	s=0
	(N-N/2).times{|j|i[j]>0&&s+=c[N/2+j]}
	q2<<s
}
q2=q2.uniq.sort
q1.each{|e|
	fidx=(0...q2.size).bsearch{|i|q2[i]>=t-e}||q2.size
	f_=([fidx-1,fidx]-[-1,q2.size]).map{|i|q2[i]}
	f_.each{|f|r=[r,(t-e-f).abs].min}
}
p r