uses crt; var S,i,n:integer; begin clrscr; write('Nhap n: '); readln(n); for i:=1 to n do if i mod 2 = 1 then S:=S+i; write('Tong la: ',S); readln end.
program oken; uses crt; var n,i,s: longint; begin clrscr; write('nhap n: '); readln(n); s:=0; for i:=1 to n do if i mod 2=1 then s:=s+i; writeln('Tong S: ',s); readln; end.