var a:array[1..4000000] of boolean;
    x:array[1..4000000] of longint;
    y:array[1..4000000] of longint;
    num:array[1..4000000] of longint;
	last:array[1..4000000] of longint;
    n,i,u,j,s:longint;total:qword;
 
function dizheng:boolean;
var i,j:longint;
begin
 for i:=1 to n-1 do
  for j:=i to n do
   if last[i]>last[j] then exit(false);
 exit(true);
end;
procedure print;
var i,a,b:longint;r,t,w:string;v:boolean;
 
begin
fillchar(last,sizeof(last),0);
v:=true;
for i:=1 to n do
for j:=s downto 1 do
 if x[j]=i then begin last[i]:=j;break;end;
if dizheng then total:=total+1;
 
end;
 
 procedure try(i:longint);
var j:longint;
begin
  for j:=1 to s do
    if a[j]=true then begin
      x[i]:=y[j];
      a[j]:=false;
      if i<s
        then try(i+1)
      else print;
      a[j]:=true;
    end;
end;
procedure same;
begin
 for i:=1 to n do
  if num[1]<>1 then exit;
 writeln(1);
 halt;
end;
 
 
begin
assign(input,'asm_formation.in');
reset(input);
assign(output,'asm_formation.out');
rewrite(output);
 
    total:=0;readln(n);
    for i:=1 to n do begin
     read(num[i]); s:=s+num[i]; end;
    u:=1;
    same;
   { for i:=1 to n do
     begin
      for j:=1 to num[i] do
       y[u]:=i;
       u:=u+1;
     end; }
     for i:=1 to n do
      for j:=1 to num[i] do
       begin
        y[u]:=i;
        u:=u+1;
       end;
    for i:=1 to s do
    a[i]:=true;
    try(1);
    total:=total div 4;
    total:=total mod 998244353;
	writeln(total);
close(input);
close(output);
end.