/VIENBI - Viên bi màu nhiệm

<Problem>

http://ntucoder.net/Problem/Details/3300
              Uses Crt;
        Var  a,b,c,i:longint;
        Begin
            readln(a,b,c);
            i:=1;
            if (a+b=0) or (a+c=0) then writeln('NO')
            else
            if (b=c) then writeln('YES')
            else
            begin
                //if abs(b-c) mod 3=0 then writeln('YES') else writeln('NO');
                if c>b then
                begin
                while (c>b) do
                begin
                    if i mod 2=1 then
                    begin
                        c:=c-1;
                        b:=b-1;
                        a:=a+2;
                    end;
                    if i mod 2=0 then
                    begin
                        c:=c-1;
                        b:=b+2;
                        a:=a-1;
                    end;
                    inc(i);
                end;
                if c=b then writeln('YES') else writeln('NO');  exit;
                end;
                i:=1;
                if (b>c) then
                begin
                    while (b>c) do
                    begin
                        if i mod 2=1 then
                        begin
                            b:=b-1;
                            c:=c-1;
                            a:=a+2;
                        end;
                        if i mod 2=0 then
                        begin
                            b:=b-1;
                            c:=c+2;
                            a:=a-1;
                        end;
                        inc(i);
                    end;
                    if b=c then writeln('YES') else writeln('NO'); exit; 
                end;
        
            end;
        End.