Sample Input file formats for finding maximum independent set program

Sample Input File 1
5->45->21->18->1->3->2->5->42->13->17->1->1->51->52->5->6->4->11->13->10

Sample Input File 2
2->3->2->8->11->2->1->1->1->16->15->6->17->1->4->18

Sample Input File 3
3->1->3->1->3->3->1->3->1->3->1

Note:
The integers are the node weights.