/** * code generated by JHelper * More info: https://github.com/AlexeyDmitriev/JHelper * @author */ #include using namespace std; using ll = long long; using ld = long double; template using P = pair; template using V = vector; using VI = vector; using VL = vector; //#pragma GCC optimize("O3") //#pragma GCC target("avx2") //#pragma GCC target("avx512f") //#pragma GCC optimize("unroll-loops") //#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") //#pragma GCC optimize("Ofast") #define G(size_1) vector>(size_1, vector()) #define SZ(x) ((long long)(x).size()) #define READ ({long long t;cin >> t;t;}) #define FOR(i, __begin, __end) for (auto i = (__begin) - ((__begin) > (__end)); i != (__end) - ((__begin) > (__end)); i += 1 - 2 * ((__begin) > (__end))) #define REP(i, __end) for (auto i = decltype(__end){0}; i < (__end); ++i) #define ALL(x) (x).begin(),(x).end() #define RALL(x) (x).rbegin(),(x).rend() #define F first #define S second #define y0 y3487465 #define y1 y8687969 #define j0 j1347829 #define j1 j234892 #define BIT(n) (1LL<<(n)) #define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() ) #define EB emplace_back #define PB push_back #define fcout cout << fixed << setprecision(12) #define fcerr cerr << fixed << setprecision(12) #define print(x) cout << (x) << '\n' #define printE(x) cout << (x) << endl; #define fprint(x) cout << fixed << setprecision(12) << (x) << '\n' # define BYE(a) do { cout << (a) << endl; return ; } while (false) #define LB lower_bound #define UB upper_bound #define LBI(c, x) distance((c).begin(), lower_bound((c).begin(), (c).end(), (x))) #define UBI(c, x) distance((c).begin(), upper_bound((c).begin(), (c).end(), (x))) #ifdef DEBUG #define DBG(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator _it(_ss); _err(cerr,_it, args); } #define ERR(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator _it(_ss); _err(std::cerr,_it, args); } #else #define DBG(args...) {}; #define ERR(args...) {}; #endif void _err(std::ostream& cerr, istream_iterator it){cerr << endl;} template void _err(std::ostream& cerr, istream_iterator it, T a, Args... args){ cerr << *it << " = " << a << " "; _err(cerr, ++it, args...); } namespace aux{ template struct seq{ }; template struct gen_seq : gen_seq{ }; template struct gen_seq<0, Is...> : seq{ }; template void print_tuple(std::basic_ostream& os, Tuple const& t, seq){ using swallow = int[]; (void) swallow{0, (void(os << (Is == 0 ? "" : ",") << std::get(t)), 0)...}; } template void read_tuple(std::basic_istream& os, Tuple& t, seq){ using swallow = int[]; (void) swallow{0, (void(os >> std::get(t)), 0)...}; } } // aux:: template auto operator<<(std::basic_ostream& os, std::tuple const& t) -> std::basic_ostream&{ os << "("; aux::print_tuple(os, t, aux::gen_seq()); return os << ")"; } template auto operator>>(std::basic_istream& os, std::tuple& t) -> std::basic_istream&{ aux::read_tuple(os, t, aux::gen_seq()); return os; } template inline bool chmax(T& a, const T& b){ if(a < b){ a = b; return 1; } return 0; } template inline bool chmin(T& a, const T& b){ if(b < a){ a = b; return 1; } return 0; } template istream& operator>>(istream& is, pair& V){ is >> V.F >> V.S; return is; } template istream& operator>>(istream& is, vector& V){ for(auto&& ele : V)is >> ele; return is; } template ostream& operator<<(ostream& os, const vector V){ os << "["; int cnt = 0; T curr; if(!V.empty()){ for(int i = 0; i < V.size() - 1; ++i){ if(V[i] == curr)cnt++; else cnt = 0; if(cnt == 4)os << "... "; if(cnt < 4) os << i << ":" << V[i] << " "; curr = V[i]; } os << V.size() - 1 << ":" << V.back(); } os << "]\n"; return os; } template ostream& operator<<(ostream& os, const pair P){ os << "("; os << P.first << "," << P.second; os << ")"; return os; } template ostream& operator<<(ostream& os, const set V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << *it << " "; it++; } os << *it; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const unordered_set V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << *it << " "; it++; } os << *it; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const multiset V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << *it << " "; it++; } os << *it; } os << "}"; return os; } template ostream& operator<<(ostream& os, const map V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << "("; os << it->first << "," << it->second; os << ") "; it++; } os << "("; os << it->first << "," << it->second; os << ")"; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const unordered_map V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << "("; os << it->first << "," << it->second; os << ") "; it++; } os << "("; os << it->first << "," << it->second; os << ")"; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const deque V){ os << "["; if(!V.empty()){ for(int i = 0; i < V.size() - 1; ++i){ os << V[i] << "->"; } if(!V.empty())os << V.back(); } os << "]\n"; return os; }; template ostream& operator<<(ostream& os, const priority_queue V){ priority_queue _V = V; os << "["; if(!_V.empty()){ while(_V.size() > 1){ os << _V.top() << "->"; _V.pop(); } os << _V.top(); } os << "]\n"; return os; }; template struct y_combinator{ F f; // the lambda will be stored here // a forwarding operator(): template decltype(auto) operator()(Args&& ... args) const{ // we pass ourselves to f, then the arguments. // the lambda should take the first argument as `auto&& recurse` or similar. return f(*this, std::forward(args)...); } }; // helper function that deduces the type of the lambda: template y_combinator> recursive(F&& f){ return {std::forward(f)}; } struct hash_pair{ template size_t operator()(const pair& p) const{ auto hash1 = hash{}(p.first); auto hash2 = hash{}(p.second); return hash1^hash2; } }; template auto vec(int n, U v){ return std::vector(n, v); } template auto vec(int n, Args... args){ auto val = vec(std::forward(args)...); return std::vector(n, std::move(val)); } const double PI = 2*acos(.0); const int INF = 0x3f3f3f3f; template inline T ceil(T a, T b){return (a + b - 1)/b;} inline long long popcount(ll x){return __builtin_popcountll(x);} template struct Matrix{ typedef vector arr; typedef vector mat; mat dat; Matrix(size_t r, size_t c) : dat(r, arr(c, K())){} Matrix(mat dat) : dat(dat){} size_t size() const{return dat.size();} bool empty() const{return size() == 0;} arr& operator[](size_t k){return dat[k];} const arr& operator[](size_t k) const{return dat[k];} static Matrix cross(const Matrix& A, const Matrix& B){ Matrix res(A.size(), B[0].size()); for(int i = 0; i < (int) A.size(); i++) for(int j = 0; j < (int) B[0].size(); j++) for(int k = 0; k < (int) B.size(); k++) res[i][j] |= A[i][k]&B[k][j]; return res; } static Matrix identity(size_t n){ Matrix res(n, n); for(int i = 0; i < (int) n; i++) res[i][i] = K(1); return res; } Matrix pow(long long n) const{ assert(n >= 0); Matrix a(dat), res = identity(size()); while(n){ if(n&1) res = cross(res, a); a = cross(a, a); n >>= 1; } return res; } template using ET = enable_if::value>; template using EF = enable_if::value>; template::type* = nullptr> static bool is_zero(T x){return abs(x) < 1e-8;} template::type* = nullptr> static bool is_zero(T x){return x == T(0);} template::type* = nullptr> static bool compare(T x, T y){return abs(x) < abs(y);} template::type* = nullptr> static bool compare(T x, T y){ (void) x; return y != T(0); } // assume regularity static Matrix gauss_jordan(const Matrix& A, const Matrix& B){ int n = A.size(), l = B[0].size(); Matrix C(n, n + l); for(int i = 0; i < n; i++){ for(int j = 0; j < n; j++) C[i][j] = A[i][j]; for(int j = 0; j < l; j++) C[i][n + j] = B[i][j]; } for(int i = 0; i < n; i++){ int p = i; for(int j = i; j < n; j++) if(compare(C[p][i], C[j][i])) p = j; swap(C[i], C[p]); if(is_zero(C[i][i])) return Matrix(0, 0); for(int j = i + 1; j < n + l; j++) C[i][j] /= C[i][i]; for(int j = 0; j < n; j++){ if(i == j) continue; for(int k = i + 1; k < n + l; k++) C[j][k] -= C[j][i]*C[i][k]; } } Matrix res(n, l); for(int i = 0; i < n; i++) for(int j = 0; j < l; j++) res[i][j] = C[i][n + j]; return res; } Matrix inv() const{ Matrix B = identity(size()); return gauss_jordan(*this, B); } static arr linear_equations(const Matrix& A, const arr& b){ Matrix B(b.size(), 1); for(int i = 0; i < (int) b.size(); i++) B[i][0] = b[i]; Matrix tmp = gauss_jordan(A, B); arr res(tmp.size()); for(int i = 0; i < (int) tmp.size(); i++) res[i] = tmp[i][0]; return res; } K determinant() const{ Matrix A(dat); K res(1); int n = size(); for(int i = 0; i < n; i++){ int p = i; for(int j = i; j < n; j++) if(compare(A[p][i], A[j][i])) p = j; if(i != p) swap(A[i], A[p]), res = -res; if(is_zero(A[i][i])) return K(0); res *= A[i][i]; for(int j = i + 1; j < n; j++) A[i][j] /= A[i][i]; for(int j = i + 1; j < n; j++) for(int k = i + 1; k < n; k++) A[j][k] -= A[j][i]*A[i][k]; } return res; } static K sigma(K x, long long n){ Matrix A(2, 2); A[0][0] = x; A[0][1] = 0; A[1][0] = 1; A[1][1] = 1; return A.pow(n)[1][0]; } }; void solve(std::istream& cin, std::ostream& cout, std::ostream& cerr){ ll N, M, T; cin >> N >> M >> T; Matrix g(N, N); REP(i, M){ int a, b; cin >> a >> b; g[a][b] = 1; } int ans = 0; g = g.pow(T); DBG(g.dat) REP(i,N)ans += g[0][i]; print(ans); } #undef int int main() { istream& in(cin); ostream& out(cout); ostringstream err; in.tie(0); ios::sync_with_stdio(0); solve(in, out, err); return 0; }