Program zad4;
  var n,i,j,max,m:integer;
  a,b:array[1..20] of integer;
Begin
  read(n);
  for i:=1 to n do
    read(a[i]);
  for i:=1 to n do
    if a[i]<0 then 
    begin
      m:=m+1;
      b[m]:=a[i];
    end;
   max:=b[1];
  for i:=2 to m do
    if b[i]>max then max:=b[i];
writeln(max);
End.
  