#define _USE_MATH_DEFINES #include using namespace std; //template #define rep(i,a,b) for(int i=(a);i<(b);i++) #define rrep(i,a,b) for(int i=(a);i>(b);i--) #define ALL(v) (v).begin(),(v).end() typedef long long int ll; const int inf = 0x3fffffff; const ll INF = 0x3fffffffffffffff; template inline bool chmax(T& a,T b){ if(a inline bool chmin(T& a,T b){ if(a>b){a=b;return 1;}return 0; } //template end int main(){ int n; scanf("%d",&n); vector a(n); rep(i,0,n)scanf("%d",&a[i]); bool ans[2010]; rep(i,0,n+1)ans[i]=1; reverse(ALL(a)); rep(i,0,n){ int g=0; rep(j,0,i+1)g^=a[j]; rrep(j,i,-1){ cerr<