N
O
R
O
R
O
D
X
X
N
R
N
D
R
N
N
N
X
O
N
X
X
D
N
N
R
O
R
R
R
O
X
D
X
R
N
R
O
X
X
D
X
O
N
D
O
X
O
N
O
D
D
O
D
N
N
X
D
X
R
N
D
O
D
D
O
D
R
D
X
X
O
R
R