program oken; uses crt; var n,i,s: longint; begin clrscr; write('Nhap 1 so bat ky: '); readln(n); s:=0; for i:=1 to n do if (i mod 2=1) then s:=s+i; writeln('Tong S: ',s); writeln('Ho va Ten: {ban ghi ten o day}'); writeln('Lop: {ban ghi lop o day}'); {Nho xoa hai "dong ban ghi.."., sau khi ghi ten va lop} readln; end.