import java.util.ArrayList;
import java.util.HashMap;
class Graph
{
HashMap<String, ArrayList<String>> adjList = new HashMap<>();
public void printGraph()
{
System.out.println(adjList);
}
public boolean addVertex(String vertex)
{
if(adjList.get(vertex)==null)
{
adjList.put(vertex,new ArrayList<String>());
return true;
}
return false;
}
public boolean addEdge(String vertex1, String vertex2)
{
if(adjList.get(vertex1)!=null && adjList.get(vertex2)!=null)
{
adjList.get(vertex1).add(vertex2);
adjList.get(vertex2).add(vertex1);
return true;
}
return false;
}
public boolean removeEdge(String vertex1, String vertex2)
{
if(adjList.get(vertex1)!=null && adjList.get(vertex2)!=null)
{
adjList.get(vertex1).remove(vertex2);
adjList.get(vertex2).remove(vertex1);
return true;
}
return false;
}
}
class Main {
public static void main(String[] args) {
Graph myGraph = new Graph();
myGraph.addVertex("A");
myGraph.addVertex("B");
myGraph.addEdge("A","B");
myGraph.removeEdge("A","B");
myGraph.printGraph();
}
}
