n = gets.to_i
result = Array.new(10, true)

n.times do |i|
    arr = gets.split
    a, b, c, d, s = arr
    if s == "NO"
        result[a.to_i] = false
        result[b.to_i] = false
        result[c.to_i] = false
        result[d.to_i] = false
    end
end
puts result.index{|x| x}