var N,i,a,p:integer;
BEGIN
readln(N);
p:=1;
for i:=1 to N do begin
read(a);
if (a>9) and (a<100) then
p:=p*a;
end;
writeln(p);
end.
var N,i,a,p:integer;
BEGIN
readln(N);
p:=1;
for i:=1 to N do begin
read(a);
if (a>9) and (a<100) then
p:=p*a;
end;
writeln(p);
end.