var
  t,i,j:longint;
  ans,x,n:int64;
begin
  readln(t);
  while t>0 do
  begin
    readln(n);
    ans:=0;
    for i:=1 to n do
    begin
      read(x);
      if x>ans then ans:=x;
    end;
    writeln(ans);
    dec(t);
  end;
end.