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0 10 doc 0 0
0 1 doc 0 0
1 1 a 0 0
2 3 #text 0 1 This
1 15 a 0 0
1 1 b 0 0
2 3 #text 0 1  is a valid
1 15 b 0 0
1 1 a 0 0
2 3 #text 0 1  document
1 15 a 0 0
0 15 doc 0 0