var g,w,min,a,b,i,c,s,j,x,ct,y:integer;
    f,e:text;
BEGIN
assign(f,'energii.in');reset(f);assign(e,'energii.out');rewrite(e);
read(f,g);read(f,w);min:=-1;c:=10001;j:=0;s:=0;  ct:=0;
for i:=1 to g do
BEGIN
    readln(f,a,b);
    if a>=w then
        begin
         if (a>=w) and (b<c) then
            begin
            c:=b;
            min:=a;
            end;
        end;
    if a<w then
       BEGIN
       x:=a;y:=b;
       for j:=i+1 to g do
           begin
             readln(f,a,b);
             if a<w then
               begin
               s:=s+a;
               ct:=ct+b;
               end;
           end;
   s:=s+x;
   ct:=ct+y;
       END; reset(f);
END;

if min>=w then write (e,c) else write(e,-1);
close(f);close(e);
END.