program energetic;
var f,g:text;
   n,k,i,p,w,g,c,j:longint;
   x:array[1..3,1..100] of real;
begin
assign(f,'energii.in'); reset(f);
assign(g,'energii.out'); rewrite(g);
readln(f,n);
readln(f,w);
for i:=1 to n do begin
 readln(f,x[1,g],x[2,c]);
 x[3,k]:=x[1,g]/x[2,c];
 end;
for i:=1 to n do
       for j:=(i+1) to n do if x[3,i]<x[3,j] then begin
                          p:=x[3,i];
                          x[3,i]:=x[3,j];
                          x[3,j]:=p;
                          p:=x[1,i];
                          x[1,i]:=x[1,j];
                          x[1,j]:=p;
                          p:=x[2,i];
                          x[2,i]:=x[2,j];
                          x[2,j]:=p;
                          end;
i:=1;
c:=0;
p:=0;
while p<w do begin
     p:=p+x[1,i];
     c:=c+x[2,i];
     inc(i);
     end;
writeln(g,c);
close(f);
close(g);
end.