var
    a : array [1..12] of longint;
    b ,c ,i ,N ,max ,sum : longint;

begin
    max:=0;
    Readln(N);
    for i := 1 to N do begin
        read(a[i]);
        if max<a[i] then begin
            max:=a[i];
        end;
    end;
    for i := 1 to N do begin
        sum := sum +a[i];
    end;
    sum:=sum-max;
    if sum > max then begin
        sum := sum - 1;
        max := max + 1;
    end;
    writeln(abs(max-sum));
end.