type rucsac=record
       masa,cost,pret:integer;
       end;
       var n,i,j:byte;
           a:array[1..100] of rucsac;
           rs,g,k:real;
           x:rucsac;
           fi,fo:text;
begin   assign(fi,'rucsac.in');reset(fi);
         assign(fo,'rucsac.out');rewrite(fo);
         read(fi,n,k);
      writeln(fo,'n=',n);

      writeln(fo,'k=',k);
       for i:=1 to n do begin
            writeln(fo,'masa:',a[i].masa);
            writeln(fo,'cost:',a[i].cost);
            a[i].pret:=a[i].cost div a[i].masa;
                         end;
       for i:=1 to n-1 do
             for j:=i+1 to n do
                    if (a[i].pret<a[j].pret) then begin
                                                 x:=a[i];
                                                 a[i]:=a[j];
                                                 a[j]:=x;
                                                    end;
                 i:=1;
                  while (i<=n) and (k<=g) do
                                     if a[i].masa +k>g then  begin
                                            rs:=(g-k)*a[i].pret;
                                            break;end
                                                else begin
                                                rs:=rs+a[i].cost;
                                                k:=k+a[i].masa;
                                                inc(i);
                                            end;
                                       writeln(fo,'rs=',rs:0:5);
readln;
end.