Node[] nodes = new Node[10];
HashSet<Node> visited = new HashSet<Node>();
int count = 0;
for (int i = 0; i < nodes.Length; i++)
{
    Node current = nodes[i];
    if (visited.Contains(current)) continue;
    while (current != null)
    {
        visited.Add(current);
        current = current.Next;
        if (visited.Contains(current) || current == null)
        {
            count++;
            break;
        }
    }
}

Node[] nodes = new Node[10];
HashSet<Node> visited = new HashSet<Node>();
int count = 0;
for (int i = 0; i < nodes.Length; i++)
{
    Node current = nodes[i];
    if (visited.Contains(current)) continue;
    while (current != null)
    {
        visited.Add(current);
        current = current.Next;
        if (visited.Contains(current) || current == null)
        {
            count++;
            break;
        }
    }
}

for (int i = 0; i < 10; i++)
{

}

for (int i = 0; i < 10; i++)
{

}

List<int> inputValues = new List<int>();
for (int i = 0; i < inputValues.Count; i++)
{
    // add user's input to list
}

List<int> inputValues = new List<int>();
for (int i = 0; i < inputValues.Count; i++)
{
    // add user's input to list
}