 
										
											 7
 7  1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1 
										
											 2
 2 
										
											 1
 1 
										
											 1
 1 
										
											 1
 1
2个7-9
7-9,谢谢