uses crt;
var A : array [1 .. 100] of integer;
i, n, S : integer;
begin
clrscr;
S := 0;
write('Nhap so phan tu = '); readln(n);
write('Nhap mang gom ', n ,' so : ');
for i := 1 to n do begin read(A[i]);
if i mod 2 <> 0 then S := S + A[i]; end;
write('Tong phan tu chi so le : ', S);
readln
end.