#pragma region /* \(^o^)/ import sys 私は人間です. 吾輩はやれば出来る子である.     ∩ ∩    (´・ω・)    _| ⊃/(___  / └-(____/   ̄ ̄ ̄ ̄ ̄ ̄ ̄  やる気はまだない.    ⊂⌒/ヽ-、__  /⊂_/____ /   ̄ ̄ ̄ ̄ ̄ ̄ ̄ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; struct Init{Init(){std::cin.tie(0); ios::sync_with_stdio(false); cout << setprecision(20) << fixed;}}init; using ll = long long; using ull = unsigned long long; using ld = long double; #define all(x) begin((x)), end((x)) #define pb push_back #define mp make_pair #define mt make_tuple #define uq(v) v.erase(unique(begin(v), end(v)), end(v)) #define _overload4(_1,_2,_3,_4,name,...) name #define _overload3(_1,_2,_3,name,...) name #define _rep1(n) for(int i=0;i=0;i--) #define _rrep2(i,n) for(int i=(n)-1;i>=0;i--) #define _rrep3(i,a,b) for(int i=(b)-1;i>=(a);i--) #define _rrep4(i,a,b,c) for(int i=a+(b-a-1)/c*c;i>=a;i-=c) #define rrep(...) _overload4(__VA_ARGS__,_rrep4,_rrep3,_rrep2,_rrep1)(__VA_ARGS__) template using pq = priority_queue; template using pq_g = priority_queue, greater>; template bool chmax(T &a, const T &b){if(a < b){a = b; return 1; } return 0;} template bool chmin(T &a, const T &b){if(a > b){a = b; return 1; } return 0;} template auto min(const T& a){ return *min_element(all(a)); } template auto max(const T& a){ return *max_element(all(a)); } constexpr ull INF = (1ULL << 61) + (1ULL << 30); constexpr int inf = (1 << 30); constexpr ld EPS = 1e-9; constexpr int dx[] = {1, 0, -1, 0, 1, 1, -1, -1}; constexpr int dy[] = {0, 1 ,0, -1, 1, -1, 1, -1}; #pragma endregion template struct LambdaMonoid{ using S = S2; S op(const S &a, const S &b) const {return _op(a, b);} S e() const {return _e();} LambdaMonoid(Op _op, E _e): _op(_op), _e(_e){} private: Op _op; E _e; }; template LambdaMonoid(Op _op, E _e) -> LambdaMonoid; template struct SegmentTree{ using S = typename Monoid::S; private: int n, sz; vector seg; Monoid m; public: SegmentTree() = default; explicit SegmentTree(Monoid m, int n): m(m), n(n){ sz = 1; while(sz < n) sz <<= 1; seg.assign(2 * sz, m.e()); } explicit SegmentTree(Monoid m, const vector &v): SegmentTree(m, (int)v.size()){ build(v); } void build(const vector &v){ assert(n == (int)v.size()); for(int k = 0; k < n; ++k) seg[k + sz] = v[k]; for(int k = sz - 1; k > 0; --k){ seg[k] = m.op(seg[2 * k + 0], seg[2 * k + 1]); } } void set(int k, const S &x){ k += sz; seg[k] = x; while(k >>= 1){ seg[k] = m.op(seg[2 * k + 0], seg[2 * k + 1]); } } S get(int k) const {return seg[k + sz];} S operator[](int k) const {return get(k);} void apply(int k, const S &x){ k += sz; seg[k] = m.op(seg[k], x); while(k >>= 1){ seg[k] = m.op(seg[2 * k + 0], seg[2 * k + 1]); } } S query(int l, int r) const { if(l >= r) return m.e(); S L = m.e(), R = m.e(); for(l += sz, r += sz; l < r; l >>= 1, r >>= 1){ if(l & 1) L = m.op(L, seg[l++]); if(r & 1) R = m.op(seg[--r], R); } return m.op(L, R); } S all_query() const {return seg[1];} template int find_first(int l, const C &check) const { if(l >= n) return n; l += sz; S sum = m.e(); do{ while((l & 1) == 0) l >>= 1; if(check(m.op(sum, seg[l]))){ while(l < sz){ l <<= 1; auto nxt = m.op(sum, seg[l]); if(not check(nxt)){ sum = nxt; ++l; } } return l + 1 - sz; } sum = m.op(sum, seg[l++]); }while((l & -l) != l); return n; } template int find_last(int r, const C &check) const { if(r <= 0) return -1; r += sz; S sum = m.e(); do{ r--; while(r > 1 and (r & 1)) r >>= 1; if(check(m.op(seg[r], sum))){ while(r < sz){ r = (r << 1) + 1; auto nxt = m.op(seg[r], sum); if(not check(nxt)){ sum = nxt; r--; } } return r - sz; } sum = m.op(seg[r], sum); }while((r & -r) != r); return -1; } }; auto op = [](ll a, ll b) { return a + b; }; auto e = []() { return 0LL; }; int main(){ int N, M; cin >> N >> M; if(N % 3 != 0){ cout << 0 << "\n"; return 0; } vector v(N + 1, 0); vector vv(N + 1, 0); v[0] = 1; SegmentTree dp1(LambdaMonoid(op, e), v); rep(i, N / 3){ SegmentTree dp2(LambdaMonoid(op, e), vv); rep(j, 1, i * 3 + 2){ ll cur = dp1.query(0, j); dp2.set(j, cur % M); } swap(dp1, dp2); } cout << dp1.all_query() % M << "\n"; }