#include using namespace std; using ll = long long; using ld = long double; using VI = vector; using VL = vector; using VS = vector; template using PQ = priority_queue, greater>; #define FOR(i,a,n) for(int i=(a);i<(n);++i) #define eFOR(i,a,n) for(int i=(a);i<=(n);++i) #define rFOR(i,a,n) for(int i=(n)-1;i>=(a);--i) #define erFOR(i,a,n) for(int i=(n);i>=(a);--i) #define SORT(a) sort(a.begin(),a.end()) #define rSORT(a) sort(a.rbegin(),a.rend()) #define fSORT(a,f) sort(a.begin(),a.end(),f) #define all(a) a.begin(),a.end() #define out(y,x) ((y)<0||h<=(y)||(x)<0||w<=(x)) #define tp(a,i) get(a) #ifdef _DEBUG #define line cout << "-----------------------------\n" #define stop system("pause") #define debug(x) print(x) #endif constexpr ll INF = 1000000000; constexpr ll LLINF = 1LL << 60; constexpr ll mod = 1000000007; constexpr ll MOD = 998244353; constexpr ld eps = 1e-10; constexpr ld pi = 3.1415926535897932; templateinline bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; }return false; } templateinline bool chmin(T& a, const T& b) { if (a > b) { a = b; return true; }return false; } inline void init() { cin.tie(nullptr); cout.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } templateinline istream& operator>>(istream& is, vector& v) { for (auto& a : v)is >> a; return is; } templateinline istream& operator>>(istream& is, pair& p) { is >> p.first >> p.second; return is; } templateinline vector vec(size_t a) { return vector(a); } templateinline vector defvec(T def, size_t a) { return vector(a, def); } templateinline auto vec(size_t a, Ts... ts) { return vector(ts...))>(a, vec(ts...)); } templateinline auto defvec(T def, size_t a, Ts... ts) { return vector(def, ts...))>(a, defvec(def, ts...)); } templateinline void print(const T& a) { cout << a << "\n"; } templateinline void print(const T& a, const Ts&... ts) { cout << a << " "; print(ts...); } templateinline void print(const vector& v) { for (int i = 0; i < v.size(); ++i)cout << v[i] << (i == v.size() - 1 ? "\n" : " "); } templateinline void print(const vector>& v) { for (auto& a : v)print(a); } inline string reversed(const string& s) { string t = s; reverse(all(t)); return t; } templateinline T sum(const vector& a, int l, int r) { return a[r] - (l == 0 ? 0 : a[l - 1]); } templateinline void END(T s) { print(s); exit(0); } void END() { exit(0); } struct matrix { int n, m; vector> dat; matrix(const vector>& _a) : dat(_a) { n = dat.size(), m = dat.front().size(); } matrix(const int& _n, const int& _m) : n(_n), m(_m) { dat = vec(n, m); } matrix() {} matrix operator*=(const matrix& a) { assert(m == a.n); matrix ret(vec(n, a.m)); FOR(i, 0, n)FOR(k, 0, m)FOR(j, 0, a.m) { ret[i][j] = ret[i][j] || (dat[i][k] && a.dat[k][j]); } return *this = ret; } matrix operator*(const matrix& a) { return matrix(*this) *= a; } matrix pow(ll k) const { assert(n == m); matrix ret(vec(n, n)), a(dat); FOR(i, 0, n)ret[i][i] = true; for (; 0 < k; k >>= 1) { if (k & 1)ret *= a; a *= a; } return ret; } vector& operator[](int i) { return dat[i]; } }; int main() { init(); int n, m; ll t; cin >> n >> m >> t; matrix mat(n, n); FOR(i, 0, m) { int a, b; cin >> a >> b; mat[a][b] = true; } matrix cur(n, n); cur[0][0] = true; auto mul = cur * mat.pow(t); int ans = 0; FOR(j, 0, n)if (mul[0][j])++ans; print(ans); return 0; }