var u,ala,s,cs,min,a,b,t,aux,aux2,i,w,c,g:integer; m,n:real;
    f,e:text; ok:boolean;
    y,x,v,j:array [1..1001] of integer;
BEGIN
assign(f,'energii.in');reset(f);assign(e,'energii.out');rewrite(e);
readln(f,g);readln(f,w);c:=10001;min:=-1;ok:=false; s:=0;cs:=0;
for t:=1 to g do
y[t]:=10000;
for i:=1 to g do
    begin
    readln(f,a,b);
    v[i]:=a; j[i]:=b;
    end;
for i:=1 to g do
if v[i]>=w then ok:=true;
if ok=true then
   for i:=1 to g do
        BEGIN
        a:=v[i];b:=j[i];
        if (a>=w) and (b<c) then
        begin
             c:=b;
             min:=a;
        end;
        END;
if ok=false then
for i:=1 to g-1 do
    for t:=1 to g do
if i<t then
BEGIN
if w>s then
   begin
   s:=s+v[i]+v[t];
   cs:=cs+j[i]+j[t];
   end;
if s>=w then
        begin
        x[t]:=t;
        if cs<y[t] then y[t]:=cs;
        s:=0;cs:=0;
        end;
if w<s then y[t]:=10000;

END;

for t:=1 to g-1 do
 for u:=t+1 to g do
if (y[t]>y[u]) and (y[t]<>10000) then
   begin
   aux2:=y[t];
   y[t]:=y[u];
   y[u]:=aux2;
   end;
t:=1;
while y[t]=10000 do
t:=t+1;
if y[t]<>10000 then ala:=y[t];

if ok=false then write (e,ala);
if ok=true then write (e,c);

close(f);close(e);
end.