Driver code
static void Main ( ) { List < Tuple < int , int > > arr = new List < Tuple < int , int > > ( ) ; arr . Add ( new Tuple < int , int > ( 1 , 2 ) ) ; arr . Add ( new Tuple < int , int > ( 3 , 4 ) ) ; arr . Add ( new Tuple < int , int > ( 2 , 5 ) ) ; int N = arr . Count ;