/KUMA - Khuyến mãi (OLPCĐ 2012)

              USES CRT,MATH;
        var     k,n,t,res,temp1,temp2:int64;
                begin
                    readln(k,n,t);
                    temp1:=(n div (k+1))*k;
                    temp2:=n mod (k+1);
                    writeln((temp1+temp2)*t);
                end.