require'prime'
m=5000001
gets
b=c=l=0
gets.split.map{|a|b|=1<<a.ord-48}
z=1
Prime.each(m+10){|x|
  c<b||z=[z,[x,m].min-l].max
  y=x
  (
    c|=1<<y%10
    (c=0;l=x;break) if(b|c)>b
  )while(y/=10)>0
}
p z-2