program energie;
var a,b:array[1..1000]of integer;
    i,j,g,w:integer;
    f1,f2:text;

procedure citeste;
begin
     Assign(f1,'energii.in');reset(f1);
     Assign(f2,'energii.out');rewrite(f2);
     readln(f1,g);
     readln(f1,w);
     For i:=1 to g do begin
         read(f1,a[i],b[i]);
         readln(f1);
     end;
     close(f1);
end;

procedure ordoneaza;
begin
For i:=1 to g-1 do begin
    For j:=i+1 to g do begin
        If b[i]<b[j]then begin
           a[i]:=a[i]+a[j];
           a[j]:=a[i]-a[j];
           a[i]:=a[i]-a[j];
           b[i]:=b[i]+b[j];
           b[j]:=b[i]-b[j];
           b[i]:=b[i]-b[j];
        end;
    end;
end;
end;
procedure exit(z:integer);
begin
writeln(f2,z);
close(f2);
halt;
end;
procedure rezolva;
var s,t:integer;
begin
     s:=0;t:=0;
     For i:=1 to g do begin
         If ((s+a[i])<=w)then begin
            s:=s+a[i];
            t:=t+b[i];
         end;
         If s=w then exit(t);
     end;
end;
begin
citeste;
ordoneaza;
rezolva;
end.