{Винарский}
program z_14_29_a(input,output);
const n=20;
type T1=array[1..n] of 0..999;
     T2=array[1..n,1..n] of 0..999;

function diff1(var V: T1): integer;
var i: integer; C,B: set of 0..999;
begin
C:=[];
for i:=1 to n do
if (not(V[i] in C)) then begin diff:=diff+1; C:=C+V[i]; end;
end;

begin
var V: T1; i: integer;
for i:=1 to n do read(V[i]);
write(diff1(V));
end;