require 'prime'
require 'set'

def calc(a)
    sum = 0
    a.each do |s|
        sum += s.split('').map(&:to_i).inject(:+)
    end
    return sum
end

n = gets.to_i
arr = gets.chomp.split

if arr.uniq.size == 1
    p -1
    exit
elsif calc(arr) % 3 == 0 && !(n == 1 && arr[0].to_i == 3)
    p -1
    exit
end

ans = -1
s = Set.new()
arr.sort!.reverse!

arr.permutation(n) do |a|
    x = a.join.to_i
    if s.add?(x).nil?
        next
    end
    if x.prime?
        ans = (x > ans ? x : ans)
    end
end
p ans