How can i build a code which tells me that all the int's "connects" or not?

Question

I want to make code which tells me that can I build a path using all the dominoes or not. Here is what the input looks like:

int N = int.Parse(Console.ReadLine());
int[,] dominok = new int[N, 2];
for (int i = 0; i < N; i++)
{
    string temp =Console.ReadLine();
    dominok[i, 0] = int.Parse(temp.Split('|')[0]);
    dominok[i, 1] = int.Parse(temp.Split('|')[1]);

}

N represents the amount of dominoes, and then I add dominoes like this: 1|2, 4|1, etc.

The first idea that came to my mind was to count occurrence of all numbers and do something with that. Can someone help me with this?