var f,g:text;
i,n:integer;
v:array[1..10000] of integer;
begin
assign(f,'culori.in');
reset(f);
readln(f,n);
for i:=1 to n do readln(f,v[i]);
assign(g,'culori.out');
rewrite(g);
if v[n]<>v[1] then writeln(g,'0');
close(f);
close(g);
end.