S s1

S s1S s1S s1S s1S s1S s1
S s1S s1S s1S s1S s1S s1
S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1S s1