program tinhtong;

uses crt;

var i, n, S: integer;

begin clrsct;

        write('nhap so nguyen duong n: '); readln(n);

        for i := 1 to n do

        if i mod 2=0 then

        S:=S+i

        write('tinh tong: ',S);

        readln;

end.

program tinhtong;

uses crt;

var i, n, S: integer;

begin clrsct;

        write('nhap so nguyen duong n: '); readln(n);

        for i := 1 to n do

        if i mod 2=0 then

        S:=S+i

        write('tinh tong: ',S);

        readln;

end.

program tinhtong;

uses crt;

var i, n, S: integer;

begin clrsct;

        write('nhap so nguyen duong n: '); readln(n);

        for i := 1 to n do

        if i mod 2=0 then

        S:=S+i

        write('tinh tong: ',S);

        readln;

end.