h = {} 1.upto(10) do |i| h[i] = 0 end n = gets.to_i n.times do a, b, c = gets.split(' ').map(&:to_i) h[a] += 1 h[b] += 1 h[c] += 1 end p = 0 h.select{|k, v| v > 0}.each do |k, v| p += v / 2 h[k] = v % 2 end p += h.select{|k, v| v == 1}.size / 4 puts p