The files containing the instances have the following format:

<number of vertices>

<number of depots>
<d1 d2 ... dr>

<number of edges>
u1	u2 	cost	req
.
.
.

<number of edges that can be traversed twice>
u1	u2 	cost
.
.
.



!********************************************************************
- r represents the number of depots

- d1 d2 ... dr are the indices of the nodes where depots are located.

- For each edge connecting nodes u1 and u2 there is a line: 
	u1	u2	cost	req

where req is equal to 1 if it is a required edges and 0 otherwise