mk làm n phần tử nha
Var i , x , n : integer;
a : array [1..100] of integer ;
begin
write (' n = ') ; read (n);
x:=0;
For i:=1 to n do
begin
writeln ('a [ ' , i , '] ');
readln (a[i]);
end;
For i:=1 to n do
If (a [ i ] mod 2<> 0 ) then x:= x+a[i]);
write(' tong cac so le la ' ,x);
Readln;
End.
program ct;
var a:array[1..100] of integer;
n,i,s:integer;
begin
read(n);
for i:=1 to n do begin
read(a[i]);
end;
s:=0;
for i:=1 to n do if i mod 2=1 then s:=s+i;
write(s);
readln;
end.