"".

      . 
     ,   
      (,     
   3   ).

      d   v 
   (,     0   
  d).

 
     N -    (1<=N<=100), 
 d  v,     R (0<=R<=10000). 
 -   .     
 ,  ,   
   (  -   0  10000).  
  t    - ,    
      ,    t.

 
     ,    
   v.         
   d  v,  -1.

  
3
1 3
4
1 0 2 5
1 1 2 3
2 3 3 5
1 1 3 10

  
5
