require'prime'
m=5000001
gets
b=c=l=0
gets.split.map{|a|b|=1<<a.to_i}
z=1
Prime.each(m+10){|x|c<b||z=[z,[x,m].min-l].max
(c=0;l=x)if x.to_s.each_char.any?{|y|c|=1<<y.to_i;b|c>b}}
p z-2