#!ruby -rprime
a=u=r=m=0
gets
gets.bytes{|c|a+=1<<c-48}
Prime.each(5e6){|q|u<a||r=[r,q+~m].max;q.to_s.bytes{|c|u|=1<<c-48};u|a>a&&m=q+u=0}
p r.+r<=>4e6