#ifndef LOCAL #pragma GCC optimize("O3") #endif #include using namespace std; #define sim template muu & operator<<( #define ris return *this #define eni(r) sim> typename enable_if <1 r sizeof(dud(0)),muu&>::type operator<<(c g) { sim> struct rge {c b,e ;}; sim> rge range(c i, c j) {return rge{i, j};} sim> auto dud(c *r)-> decltype(cerr << *r); sim> char dud(...); struct muu { #ifdef LOCAL stringstream a; ~muu() {cerr << a.str() << endl;} eni(<) a << boolalpha << g; ris;} eni(==) ris << range(begin(g), end(g));} sim, class m mor pair r) {ris << "(" << r.first << ", " << r.second << ")";} sim mor rge u) { a << "["; for (c i = u.b; i != u.e; ++i) *this << ", " + 2 * (i == u.b) << *i; ris << "]"; } #else sim mor const c&) {ris;} #endif muu & operator()(){ris;} }; #define debug (muu() << __FUNCTION__ << "#" << __LINE__ << ": ") #define imie(r) "[" #r ": " << (r) << "] " #define imask(r) "[" #r ": " << bitset<8 * sizeof(r)>(r) << "] " #define arr(a, i) "[" #a imie(i) ": " << a[i] << "] " #define arr2(a, i, j) "[" #a imie(i) imie(j) ": " << a[i][j] << "] " using ll=long long; const int nax=1000*1007; ll dp[nax]; ll jed[nax]; ll dwa[nax]; ll trz[nax]; void test() { int n; scanf("%d", &n); debug() << jed[n] << " " << dwa[n] << " " << trz[n]; printf("%lld\n", (jed[n]-dwa[n]*3+2*trz[n])/6); } int main() { dp[1]=1; for (int h=1; h<=3; h++) for (int i=nax-1; i; i--) for (int j=2*i; j