var f,g:text;
n,i,k,l:longint;
a:array[1..1000] of longint;
begin
assign(f,'culori.in');
assign(g,'culori.out');
reset(F);readln(f,n);
rewrite(G);
for i:=1 to 2*n-1 do readln(f,a[i]);
if a[i]<>a[2*n-1] then writeln(g,0)
                  else begin
                       randomize;
                       k:=random(9901);
                       writeln(g,k);
                       end;
close(F);
close(G);
end.