program pascal;  
 var f,h:text; i,j,n,g,min:longint;  
     y,c,gr:array[0..20000] of longint;  
  procedure citire;  
  begin  
  assign(f,'energii.in'); reset(f);  
  assign(h,'energii.out'); rewrite(h);  
  readln(f,n); readln(f,g);  
  for i:=1 to n do  
         readln(f,c[i],gr[i]);  
  close(f);  
  end;  
   
  procedure dinamik;  
  begin  
  y[0]:=0;  
  for i:=1 to 20000 do y[i]:=maxlongint;  
  for i:=1 to n do  
  for j:=g downto 0 do  
   if y[j]<>maxlongint then  
            if y[j]+gr[i]<y[j+c[i]] then y[j+c[i]]:=y[j]+gr[i];  
   min:=maxlongint;  
   for i:=g to 20000 do  
     
   if min=maxlongint then min:=-1;  
  end;  
   
  procedure afisare;  
  begin  
  write(h,min);  
  close(h);  
  end;  
   
 begin  
 citire;  
 dinamik;  
 afisare; 
end.