n = gets.to_i
a = Array.new
n.times do
    s = gets
    max_c = "1"
    s.each_char do |x|
        max_c = x if x.ord > max_c.ord
    end
    base = 2
    if max_c.ord >= "1".ord && max_c.ord <= "9".ord
        base = max_c.ord - 48 + 1
    else
        base = max_c.ord - 55 + 1
    end
    a.push(s.to_i(base))
end
puts a.min