aNs = []
gets.to_i.times{
    n = gets
    break if n.include?(" ")
    aNs << n.to_i
}
if aNs.size == 3
    sums = aNs.combination(2).to_a.map{|v| v.inject(:+)}.uniq.sort.reverse
    puts sums.size == 1 ? "assert" : sums[1]
else
    puts "assert"
end