/* #region header */ #pragma GCC optimize("O3") //コンパイラ最適化用 #ifdef LOCAL #define _GLIBCXX_DEBUG //配列に[]でアクセス時のエラー表示 #endif #define _USE_MATH_DEFINES #include //sort,二分探索,など #include // CodeForcesの場合ファイルごとに入れる #include //固定長bit集合 // #include // #include #include //assert(p)で,not pのときにエラー #include #include //実行時間計測 #include #include //pow,logなど #include //複素数 #include #include #include #include //sortのgreater #include //setprecision(浮動小数点の出力の誤差) #include // std::left, std::right #include //入出力 #include //集合演算(積集合,和集合,差集合など) #include #include //iota(整数列の生成),gcdとlcm,accumulate #include #include #include #include #include #include #include #include //pair #include using namespace std; using namespace atcoder; typedef long long LL; typedef long double LD; #define ALL(x) x.begin(), x.end() const long long INF = numeric_limits::max() / 4; const int MOD = 1e9 + 7; // const int MOD=998244353; //略記 #define FF first #define SS second #define int long long #define stoi stoll #define LD long double #define PII pair #define PB push_back #define EB emplace_back #define MP make_pair #define SZ(x) (int)((x).size()) #define VB vector #define VVB vector> #define VI vector #define VVI vector> #define REP(i, n) for (int i = 0; i < (int)(n); i++) #define REPD(i, n) for (int i = (int)(n) - (int)1; i >= 0; i--) #define FOR(i, a, b) for (int i = a; i < (int)(b); i++) #define FORD(i, a, b) for (int i = (int)(b) - (int)1; i >= (int)a; i--) const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0}; const int Dx[8] = {0, 1, 1, 1, 0, -1, -1, -1}, Dy[8] = {-1, -1, 0, 1, 1, 1, 0, -1}; int in() { int x; cin >> x; return x; } // https://qiita.com/Lily0727K/items/06cb1d6da8a436369eed#c%E3%81%A7%E3%81%AE%E5%AE%9F%E8%A3%85 void print() { cout << "\n"; } template void print(Head &&head, Tail &&...tail) { cout << head; if (sizeof...(tail) != 0) cout << " "; print(forward(tail)...); } template void print(vector &vec) { for (auto &a : vec) { cout << a; if (&a != &vec.back()) cout << " "; } cout << "\n"; } template void print(set &set) { for (auto &a : set) { cout << a << " "; } cout << "\n"; } template void print(vector> &df) { for (auto &vec : df) { print(vec); } } // debug macro // https://atcoder.jp/contests/abc202/submissions/22815715 namespace debugger { template void view(const std::vector &a) { std::cerr << "{ "; for (const auto &v : a) { std::cerr << v << ", "; } std::cerr << "\b\b }"; } template void view(const std::vector> &a) { std::cerr << "{\n"; for (const auto &v : a) { std::cerr << "\t"; view(v); std::cerr << "\n"; } std::cerr << "}"; } template void view(const std::vector> &a) { std::cerr << "{\n"; for (const auto &p : a) std::cerr << "\t(" << p.first << ", " << p.second << ")\n"; std::cerr << "}"; } template void view(const std::map &m) { std::cerr << "{\n"; for (const auto &p : m) std::cerr << "\t[" << p.first << "] : " << p.second << "\n"; std::cerr << "}"; } template void view(const std::pair &p) { std::cerr << "(" << p.first << ", " << p.second << ")"; } template void view(const std::set &s) { std::cerr << "{ "; for (auto &v : s) { view(v); std::cerr << ", "; } std::cerr << "\b\b }"; } template void view(const T &e) { std::cerr << e; } } // namespace debugger #ifdef LOCAL void debug_out() {} template void debug_out(Head H, Tail... T) { debugger::view(H); std::cerr << ", "; debug_out(T...); } #define debug(...) \ do { \ std::cerr << __LINE__ << " [" << #__VA_ARGS__ << "] : ["; \ debug_out(__VA_ARGS__); \ std::cerr << "\b\b]\n"; \ } while (false) #else #define debug(...) (void(0)) #endif long long power(long long x, long long n) { // O(logn) // https://algo-logic.info/calc-pow/#toc_id_1_2 long long ret = 1; while (n > 0) { if (n & 1) ret *= x; // n の最下位bitが 1 ならば x^(2^i) をかける x *= x; n >>= 1; // n を1bit 左にずらす } return ret; } // @brief nCr. O(r log n)。あるいは前処理 O(n), 本処理 O(1)で求められる modint // の bc を検討。 int comb(int n, int r) { // https://www.geeksforgeeks.org/program-to-calculate-the-value-of-ncr-efficiently/ if (n < r) return 0; // p holds the value of n*(n-1)*(n-2)..., // k holds the value of r*(r-1)... long long p = 1, k = 1; // C(n, r) == C(n, n-r), // choosing the smaller value if (n - r < r) r = n - r; if (r != 0) { while (r) { p *= n; k *= r; // gcd of p, k long long m = __gcd(p, k); // dividing by gcd, to simplify // product division by their gcd // saves from the overflow p /= m; k /= m; n--; r--; } // k should be simplified to 1 // as C(n, r) is a natural number // (denominator should be 1 ) . } else p = 1; // if our approach is correct p = ans and k =1 return p; } // MOD void add(long long &a, long long b) { a += b; if (a >= MOD) a -= MOD; } template inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } // 負数も含む丸め long long ceildiv(long long a, long long b) { if (b < 0) a = -a, b = -b; if (a >= 0) return (a + b - 1) / b; else return a / b; } long long floordiv(long long a, long long b) { if (b < 0) a = -a, b = -b; if (a >= 0) return a / b; else return (a - b + 1) / b; } long long floorsqrt(long long x) { assert(x >= 0); long long ok = 0; long long ng = 1; while (ng * ng <= x) ng <<= 1; while (ng - ok > 1) { long long mid = (ng + ok) >> 1; if (mid * mid <= x) ok = mid; else ng = mid; } return ok; } // @brief a^n mod mod long long modpower(long long a, long long n, long long mod) { long long res = 1; while (n > 0) { if (n & 1) res = res * a % mod; a = a * a % mod; n >>= 1; } return res; } // @brief s が c を含むか template bool contain(const std::string &s, const T &c) { return s.find(c) != std::string::npos; } __attribute__((constructor)) void faster_io() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cerr.tie(nullptr); } /* #endregion */ /* #region Math Formal Power Series */ // 二項係数ライブラリ template struct BiCoef { vector fact_, inv_, finv_; constexpr BiCoef() {} constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) { init(n); } // @brief O(n) constexpr void init(int n, int mod) noexcept { fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1); int MOD = mod; for (int i = 2; i < n; i++) { fact_[i] = fact_[i - 1] * i; inv_[i] = -inv_[MOD % i] * (MOD / i); finv_[i] = finv_[i - 1] * inv_[i]; } } // @brief O(1) constexpr T com(int n, int k) const noexcept { if (n < k || n < 0 || k < 0) return 0; return fact_[n] * finv_[k] * finv_[n - k]; } // @brief O(1) constexpr T fact(int n) const noexcept { if (n < 0) return 0; return fact_[n]; } // @brief O(1) constexpr T perm(int n, int k) const noexcept { if (n < k || n < 0 || k < 0) return 0; return fact_[n] * finv_[k] * finv_[n - k] * fact_[k]; } // @brief O(1) constexpr T inv(int n) const noexcept { if (n < 0) return 0; return inv_[n]; } // @brief O(1) constexpr T finv(int n) const noexcept { if (n < 0) return 0; return finv_[n]; } }; enum Mode { FAST = 1, NAIVE = -1, }; template struct FormalPowerSeries : std::vector { using std::vector::vector; using std::vector::size; using std::vector::resize; using std::vector::begin; using std::vector::insert; using std::vector::erase; using F = FormalPowerSeries; using S = std::vector>; F &operator+=(const F &g) { for (int i = 0; i < (int)(std::min((*this).size(), g.size())); i++) (*this)[i] += g[i]; return *this; } F &operator+=(const T &t) { assert((int)((*this).size())); (*this)[0] += t; return *this; } F &operator-=(const F &g) { for (int i = 0; i < (int)(std::min((*this).size(), g.size())); i++) (*this)[i] -= g[i]; return *this; } F &operator-=(const T &t) { assert(SZ((*this))); (*this)[0] -= t; return *this; } F &operator*=(const T &t) { for (int i = 0; i < SZ((*this)); ++i) (*this)[i] *= t; return *this; } F &operator/=(const T &t) { T div = t.inv(); for (int i = 0; i < SZ(*this); ++i) (*this)[i] *= div; return *this; } F &operator>>=(const int sz) { assert(sz >= 0); int n = (*this).size(); (*this).erase((*this).begin(), (*this).begin() + std::min(sz, n)); (*this).resize(n); return *this; } F &operator<<=(const int sz) { assert(sz >= 0); int n = (*this).size(); (*this).insert((*this).begin(), sz, T(0)); (*this).resize(n); return *this; } F &operator%=(const F &g) { return *this -= *this / g * g; } F &operator=(const std::vector &v) { int n = (*this).size(); for (int i = 0; i < n; ++i) (*this)[i] = v[i]; return *this; } F operator-() const { F ret = *this; return ret * -1; } F &operator*=(const F &g) { if (mode == FAST) { int n = (*this).size(); auto tmp = atcoder::convolution(*this, g); for (int i = 0; i < n; ++i) (*this)[i] = tmp[i]; return *this; } else { int n = (*this).size(), m = g.size(); for (int i = n - 1; i >= 0; --i) { (*this)[i] *= g[0]; for (int j = 1; j < std::min(i + 1, m); j++) (*this)[i] += (*this)[i - j] * g[j]; } return *this; } } F &operator/=(const F &g) { if ((*this).size() < g.size()) { (*this).assign((*this).size(), T(0)); return *this; } if (mode == FAST) { int old = (*this).size(); int n = (*this).size() - g.size() + 1; *this = ((*this).rev().pre(n) * g.rev().inv(n)); (*this).rev_inplace(); (*this).resize(old); return *this; } else { assert(g[0] != T(0)); T ig0 = g[0].inv(); int n = (*this).size(), m = g.size(); for (int i = 0; i < n; ++i) { for (int j = 1; j < std::min(i + 1, m); ++j) (*this)[i] -= (*this)[i - j] * g[j]; (*this)[i] *= ig0; } return *this; } } F &operator*=(S g) { int n = (*this).size(); auto [d, c] = g.front(); if (!d) g.erase(g.begin()); else c = 0; for (int i = n - 1; i >= 0; --i) { (*this)[i] *= c; for (auto &[j, b] : g) { if (j > i) break; (*this)[i] += (*this)[i - j] * b; } } return *this; } F &operator/=(S g) { int n = (*this).size(); auto [d, c] = g.front(); assert(!d and c != 0); T ic = c.inv(); g.erase(g.begin()); for (int i = 0; i < n; ++i) { for (auto &[j, b] : g) { if (j > i) break; (*this)[i] -= (*this)[i - j] * b; } (*this)[i] *= ic; } return *this; } F operator+(const F &g) const { return F(*this) += g; } F operator+(const T &t) const { return F(*this) += t; } F operator-(const F &g) const { return F(*this) -= g; } F operator-(const T &t) const { return F(*this) -= t; } F operator*(const F &g) const { return F(*this) *= g; } F operator*(const T &t) const { return F(*this) *= t; } F operator/(const F &g) const { return F(*this) /= g; } F operator/(const T &t) const { return F(*this) /= t; } F operator%(const F &g) const { return F(*this) %= g; } F operator*=(const S &g) const { return F(*this) *= g; } F operator/=(const S &g) const { return F(*this) /= g; } F pre(int d) const { return F((*this).begin(), (*this).begin() + std::min((int)(*this).size(), d)); } F &shrink() { while (!(*this).empty() and (*this).back() == T(0)) (*this).pop_back(); return *this; } F &rev_inplace() { reverse((*this).begin(), (*this).end()); return *this; } F rev() const { return F(*this).rev_inplace(); } // *=(1 + cz^d) F &multiply(const int d, const T c) { int n = (*this).size(); if (c == T(1)) for (int i = n - d - 1; i >= 0; --i) (*this)[i + d] += (*this)[i]; else if (c == T(-1)) for (int i = n - d - 1; i >= 0; --i) (*this)[i + d] -= (*this)[i]; else for (int i = n - d - 1; i >= 0; --i) (*this)[i + d] += (*this)[i] * c; return *this; } // /=(1 + cz^d) F ÷(const int d, const T c) { int n = (*this).size(); if (c == T(1)) for (int i = 0; i < n - d; ++i) (*this)[i + d] -= (*this)[i]; else if (c == T(-1)) for (int i = 0; i < n - d; ++i) (*this)[i + d] += (*this)[i]; else for (int i = 0; i < n - d; ++i) (*this)[i + d] -= (*this)[i] * c; return *this; } // @brief O(N) T eval(const T &t) const { int n = (*this).size(); T res = 0, tmp = 1; for (int i = 0; i < n; ++i) res += (*this)[i] * tmp, tmp *= t; return res; } // @brief O(n log n). FAST のみ F inv(int deg = -1) const { int n = (*this).size(); assert(mode == FAST and n and (*this)[0] != 0); if (deg == -1) deg = n; assert(deg > 0); F res{(*this)[0].inv()}; while (SZ(res) < deg) { int m = res.size(); F f((*this).begin(), (*this).begin() + std::min(n, m * 2)), r(res); f.resize(m * 2), atcoder::internal::butterfly(f); r.resize(m * 2), atcoder::internal::butterfly(r); for (int i = 0; i < m * 2; ++i) f[i] *= r[i]; atcoder::internal::butterfly_inv(f); f.erase(f.begin(), f.begin() + m); f.resize(m * 2), atcoder::internal::butterfly(f); for (int i = 0; i < m * 2; ++i) f[i] *= r[i]; atcoder::internal::butterfly_inv(f); T iz = T(m * 2).inv(); iz *= -iz; for (int i = 0; i < m; ++i) f[i] *= iz; res.insert(res.end(), f.begin(), f.begin() + m); } res.resize(deg); return res; } // @brief Ο(N) F &diff_inplace() { int n = (*this).size(); for (int i = 1; i < n; ++i) (*this)[i - 1] = (*this)[i] * i; (*this)[n - 1] = 0; return *this; } F diff() const { F(*this).diff_inplace(); } // @brief Ο(N) F &integral_inplace() { int n = (*this).size(), mod = T::mod(); std::vector inv(n); { inv[1] = 1; for (int i = 2; i < n; ++i) inv[i] = T(mod) - inv[mod % i] * (mod / i); } for (int i = n - 2; i >= 0; --i) (*this)[i + 1] = (*this)[i] * inv[i + 1]; (*this)[0] = 0; return *this; } F integral() const { return F(*this).integral_inplace(); } // @brief Ο(NlogN). FAST のみ F &log_inplace() { int n = (*this).size(); assert(n and (*this)[0] == 1); F f_inv = (*this).inv(); (*this).diff_inplace(); (*this) *= f_inv; (*this).integral_inplace(); return *this; } F log() const { return F(*this).log_inplace(); } //Ο(NlogN) F &deriv_inplace() { int n = (*this).size(); assert(n); for (int i = 2; i < n; ++i) (*this)[i] *= i; (*this).erase((*this).begin()); (*this).push_back(0); return *this; } F deriv() const { return F(*this).deriv_inplace(); } // @brief Ο(NlogN). FAST のみ F &exp_inplace() { int n = (*this).size(); assert(n and (*this)[0] == 0); F g{1}; (*this)[0] = 1; F h_drv((*this).deriv()); for (int m = 1; m < n; m *= 2) { F f((*this).begin(), (*this).begin() + m); f.resize(2 * m), atcoder::internal::butterfly(f); auto mult_f = [&](F &p) { p.resize(2 * m); atcoder::internal::butterfly(p); for (int i = 0; i < 2 * m; ++i) p[i] *= f[i]; atcoder::internal::butterfly_inv(p); p /= 2 * m; }; if (m > 1) { F g_(g); g_.resize(2 * m), atcoder::internal::butterfly(g_); for (int i = 0; i < 2 * m; ++i) g_[i] *= g_[i] * f[i]; atcoder::internal::butterfly_inv(g_); T iz = T(-2 * m).inv(); g_ *= iz; g.insert(g.end(), g_.begin() + m / 2, g_.begin() + m); } F t((*this).begin(), (*this).begin() + m); t.deriv_inplace(); { F r{h_drv.begin(), h_drv.begin() + m - 1}; mult_f(r); for (int i = 0; i < m; ++i) t[i] -= r[i] + r[m + i]; } t.insert(t.begin(), t.back()); t.pop_back(); t *= g; F v((*this).begin() + m, (*this).begin() + std::min(n, 2 * m)); v.resize(m); t.insert(t.begin(), m - 1, 0); t.push_back(0); t.integral_inplace(); for (int i = 0; i < m; ++i) v[i] -= t[m + i]; mult_f(v); for (int i = 0; i < std::min(n - m, m); ++i) (*this)[m + i] = v[i]; } return *this; } F exp() const { return F(*this).exp_inplace(); } // @brief Ο(NlogN). FAST のみ F &pow_inplace(long long k) { int n = (*this).size(), l = 0; assert(k >= 0); if (!k) { for (int i = 0; i < n; ++i) (*this)[i] = !i; return *this; } while (l < n and (*this)[l] == 0) ++l; if (l > (n - 1) / k or l == n) return *this = F(n); T c = (*this)[l]; (*this).erase((*this).begin(), (*this).begin() + l); (*this) /= c; (*this).log_inplace(); (*this).resize(n - l * k); (*this) *= k; (*this).exp_inplace(); (*this) *= c.pow(k); (*this).insert((*this).begin(), l * k, 0); return *this; } // @brief Ο(NlogN). FAST のみ F pow(const long long k) const { return F(*this).pow_inplace(k); } // @brief Ο(NlogN). FAST のみ F sqrt(int deg = -1) const { auto SQRT = [&](T t) { int mod = T::mod(); if (t == 0 or t == 1) return t; int v = (mod - 1) / 2; if (t.pow(v) != 1) return T(-1); int q = mod - 1, m = 0; while (~q & 1) q >>= 1, m++; std::mt19937 mt; T z = mt(); while (z.pow(v) != mod - 1) z = mt(); T c = z.pow(q), u = t.pow(q), r = t.pow((q + 1) / 2); for (; m > 1; m--) { T tmp = u.pow(1 << (m - 2)); if (tmp != 1) r = r * c, u = u * c * c; c = c * c; } return T(std::min(r.val(), mod - r.val())); }; int n = (*this).size(); if (deg == -1) deg = n; if ((*this)[0] == 0) { for (int i = 1; i < n; i++) { if ((*this)[i] != 0) { if (i & 1) return F(0); if (deg - i / 2 <= 0) break; auto ret = (*this); ret >>= i; ret.resize(n - i); ret = ret.sqrt(deg - i / 2); if (ret.empty()) return F(0); ret <<= (i / 2); ret.resize(deg); return ret; } } return F(deg); } auto sqr = SQRT((*this)[0]); if (sqr * sqr != (*this)[0]) return F(0); F ret{sqr}; T ti = T(1) / T(2); for (int i = 1; i < deg; i <<= 1) { auto u = (*this); u.resize(i << 1); ret = (ret.inv(i << 1) * u + ret) * ti; } ret.resize(deg); return ret; } // WARNING: TODO void sparse_pow(const int n, const int d, const T c, const int k); void sparse_pow_inv(const int n, const int d, const T c, const int k); void stirling_first(int n); void stirling_second(int n); std::vector multipoint_evaluation(const std::vector &p); // @brief O(_MAX log n) F &binomial_neg(int r, int d, int _MAX, BiCoef &bc) { REP(n, _MAX) { (*this)[n] = bc.com(n + d - 1, d - 1) * T(r).pow(n); } return *this; } }; /* #endregion Math Formal Power Series */ /* #region barlekamp_massey_and_bostan_mori */ template F Berlekamp_Massey(const F &a) { using T = typename F::value_type; int n = a.size(); F c{-1}, c2{0}; T r2 = 1; int i2 = -1; for (int i = 0; i < n; i++) { T r = 0; int d = c.size(); for (int j = 0; j < d; j++) r += c[j] * a[i - j]; if (r == 0) continue; T coef = -r / r2; int d2 = c2.size(); if (d - i >= d2 - i2) { for (int j = 0; j < d2; j++) c[j + i - i2] += c2[j] * coef; } else { F tmp(c); c.resize(d2 + i - i2); for (int j = 0; j < d2; j++) c[j + i - i2] += c2[j] * coef; c2 = std::move(tmp); i2 = i, r2 = r; } } return {c.begin() + 1, c.end()}; } // return generating function of a, s.t. F(x) = P(x) / Q(x) template std::pair find_generating_function(F a) { auto q = Berlekamp_Massey(a); int d = q.size(); a.resize(d); q.insert(q.begin(), 1); for (int i = 1; i < (int)q.size(); i++) q[i] *= -1; a *= q; return {a, q}; } // return [x^k] p(x) / q(x) template T compute_Kthterm(FormalPowerSeries p, FormalPowerSeries q, long long k) { int d = q.size(); assert(q[0] == 1 and p.size() + 1 <= d); while (k) { auto q_minus = q; for (int i = 1; i < d; i += 2) q_minus[i] *= -1; p.resize(2 * d); q.resize(2 * d); p *= q_minus; q *= q_minus; for (int i = 0; i < d - 1; i++) p[i] = p[(i << 1) | (k & 1)]; for (int i = 0; i < d; i++) q[i] = q[i << 1]; p.resize(d - 1); q.resize(d); k >>= 1; } return p[0]; } template T compute_Kthterm( std::pair, FormalPowerSeries> f, long long k) { return compute_Kthterm(f.first, f.second, k); } /* #endregion barlekamp_massey_and_bostan_mori */ using mint = modint1000000007; using fps = FormalPowerSeries; int p, q, r, K; signed main() { cin >> p >> q >> r >> K; // https://yukicoder.me/submissions/655024 int n = 100000; fps a(n, 1); a[0] = p % 10, a[1] = q % 10, a[2] = r % 10; FOR(ni, 3, n) { a[ni] = (a[ni - 3].val() + a[ni - 2].val() + a[ni - 1].val()) % 10; } // REP(ni, n) { cerr << a[ni].val() << " "; } // debug(); auto f = find_generating_function(a); print(compute_Kthterm(f, K - 1).val() % 10); }