 " "

       
   .

 :
      N  M (1 <= N <= 100; 1 <= M
<= 6000),  N -    ,  M -  .
  M      A, B, C,  A  B - 
,  ,  C -   ( ,
  30000)

 :
   -  .

  
3 3
1 2 1
2 3 2
3 1 3

  
3
