var ff:boolean;ans,tot,mm:int64;max,maxi,k,i:longint;sum:array[1..10005]of longint;
function f(x:longint):longint;
var s:int64;j:longint;
begin
s:=1;
for j:=1 to x do
s:=s*j;
exit(s);
end;
procedure js;
var a,b:int64;
begin
a:=0;b:=1;
for i:=1 to k do a:=a+sum[i];a:=f(a);
for i:=1 to k do b:=b*f(sum[i]);
ans:=a div b;
end;
begin
assign(input,'asm_formation.in');
assign(output,'asm_formation.out');
reset(input);
rewrite(output);
tot:=0;
max:=-maxlongint;
read(k);
for i:=1 to k do
begin
read(sum[i]);
if sum[i]>max then begin max:=sum[i];maxi:=i;end;
end;
mm:=7*17*223+1;
while sum[maxi]>0 do
begin
ff:=true;
ans:=0;
for i:=1 to k do
if sum[i]>0 then
dec(sum[i]);
if sum[maxi]<>0 then
js;
if sum[maxi]=0 then
begin
for i:=1 to k do
if sum[i]<>0 then
 ff:=false;
if ff then inc(tot);
end;
tot:=tot+ans;
end;
write(tot);
close(input);
close(output);
end.