**Objective**: Given undirected graph write an algorithm to count the number of non reachable vertices from a given vertex

**Example**:

**Approach**:

Use DFS

- Do the DFS (Depth-First Search) from the given vertex A, Recursively do the DFS from all the adjacent vertices of given vertex A.
- Use the visited array to keep track of visited vertices.
- Once the DFS is completed, count the number of false in visited array. These are the vertices which did not get visit.

**Code**:

**Output**:

Number of non reachable vertices from the vertex 0 are: 4 Number of non reachable vertices from the vertex 6 are: 5