Find the first circular tour that visits all gas station or petrol bunks

Find the first circular tour that visits all gas station or petrol bunks where there are N gas stations are there in a circle. 

You are given two sets of data:

1. The amount of gas/petrol that every petrol pump has.
2. Distance from that gas/petrol pump to the next petrol pump.

Node node1 = new Node("1", 6, 4);

"1" is the gas station name.

6 is amount of gas can be filled at gas station "1"

4 is the distance from current gas station to next one.

Calculate the first point from where a truck will be able to complete the circle 

Input 1

Node node1 = new Node("1", 6, 4);
Node node2 = new Node("2", 3, 6);
Node node3 = new Node("3", 7, 3);

Output
Execution 1: 3

Input 2

Node node1 = new Node("1", 4, 6);
Node node2 = new Node("2", 6, 5);
Node node3 = new Node("3", 7, 3);
Node node4 = new Node("4", 4, 5);

Output

Execution 2: 2