program phuongt;
uses crt;
var X: array[1..500] of integer;
n, i, s: integer;
begin
clrscr;
write('Nhap n = '); readln(n);
i:=1; s:=0;
while i<=n do
begin
write('X[', i, '] = '); readln(X[i]);
if X[i] mod 3 = 0 then s:=s+X[i];
i:=i+1;
end;
write('Tong = ', s);
readln
end.