V 20 E R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1 R 1