ans = []

gets.to_i.times{
    v = gets.chomp
    max = v.split('').max
    if max == '0'
        n = 2
    elsif max <= '9'
        n = max.to_i + 1
    else
        n = max.ord - 54
    end
    ans.push(v.to_i(n))
    }

p ans.min