var n,i,s:integer;
a: array [1..500] of integer;
begin
write('Nhap n: '); readln(n);
for i:=1 to n do
begin
write('Nhap phan tu thu ',i,' : '; read(a[i]);
if a[i] mod 3 = 0 then s:=s+a[i];
end;
writeln;
write('Tong cac phan tu chia het cho 3 la: ',s);
readln;
end.