// AdjacencyMatrix.java

class Graph {
    private int[][] matrix;
    int size;

    // start with no edges at all
    public Graph(int size) {
        this.size = size;
        matrix = new int[size][size];

        for(int i = 0; i < size; i++) {
            for(int j = 0; j < size; j++) {
                matrix[i][j] = 0;
            }
        }
    }

    // insert an edge
    public void insertEdge(int from, int to, int cost) {
        matrix[from][to] = cost;
    }

    // remove an edge
    public void remove(int from, int to) {
        matrix[from][to] = 0;
    }

    // return the cost of an edge or 0 for none
    public int getCost(int from, int to) {
        return matrix[from][to];
    }
}

public class AdjacencyMatrix {
    public static void main(String args[]) {
        // create a graph with 6 nodes
        Graph graph = new Graph(6);

        // add the edges
        graph.insertEdge(0, 3, 15);
        graph.insertEdge(0, 4, 20);

        graph.insertEdge(1, 5, 25);

        graph.insertEdge(3, 0, 15);
        graph.insertEdge(3, 1, 25);

        graph.insertEdge(4, 2, 30);
        graph.insertEdge(4, 5, 10);

        graph.insertEdge(5, 1, 25);
    }
}