program ex_1;
var a,b,c,n,i,total,temp:longint;
    j:boolean;
begin
  assign(input,'goz.in'); reset(input);
  assign(output,'goz.out'); rewrite(output);
  readln(n);
  j:=false; temp:=maxlongint;
  for i:=1 to n do
  begin
    readln(a,b);
    if a>=b then begin
                   total:=total+a;
                   j:=true;
                 end
    else begin
           total:=total+b;
           c:=b-a;
           if c<temp then temp:=c;
         end;
  end;
  if j then writeln(total)
       else writeln(total-c);
  close(input); close(output);
end.