To determine the number of items in a list, use the N Items() function.
x = {1, 2, y, Sqrt( 3 ), {a, b, 3}};
N = N Items( x );
Show( n );
n = 5;
x = {1, 2, y, Sqrt( 3 ), {a, b, 3}};
N = N Items( x );
Show( n );
n = 5;