var n,i,max,ans,t,s,sum:longint;
    a,w:array[0..2000]of longint;
begin

 readln(n);
 a[0]:=0;
 for i:=1 to n do begin
  read(t);
  a[i]:=t+a[i-1];
  w[i]:=t;
 end;
 max:=-maxlongint;
 for s:=1 to n do begin
  ans:=0;
  sum:=0;
  for i:=s to n do begin
  ans:=ans+a[i]-a[i-1]+sum;
  sum:=sum+w[i];
  if (ans>max) then max:=ans;
 end;
 end;
 writeln(max);
 close(input);
 close(output);
end.