read_line.to_i.times do
  puts solve() ? "Yes" : "No"
end

def solve
  n = read_line.to_i
  xys = Array.new(n) { read_line.split }
  max = -1
  xys.select { |v| v[0] == "a" }.each do |xy|
    y = xy[1]
    return true if y.includes?('a')
    max = {max, y.size}.max
  end
  min = xys.select { |v| !v[0].includes?('a') }.min_of? { |v| v[0].size }
  !min.nil? && min <= max
end