#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit32(x) (1 << (x))
#define bit64(x) (1ll << (x))

using namespace std;

using i32 = int;
using i64 = long long;
using u64 = unsigned long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vu64 = vector<u64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); return a / gcd(a, b) * b; }
inline u64 xorshift() { static u64 x = 88172645463325252ull; x = x ^ (x << 7); return x = x ^ (x >> 9); }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T exp(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> inline T bis(T ok, T ng, function<bool(T)> f, T eps = 1) { while (abs(ok - ng) > eps) { T mi = (ok + ng) / 2; (f(mi) ? ok : ng) = mi; } return ok; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { each(x, v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }

template <typename T>
struct WeightedGraph {
  struct Edge {
    int to;
    T cost;
  };
  vector<vector<Edge>> edges;
  int n;
  WeightedGraph(int n) : n(n) {
    edges = vector<vector<Edge>>(n);
  }
  void add_edge(int from, int to, T cost = 0) {
    edges[from].push_back((Edge) { to, cost });
  }
  vector<Edge>& operator[](int x) {
    return edges[x];
  }
};

template <typename T>
vector<T> bellman_ford(WeightedGraph<T> &g, int s) {
  const T INF = numeric_limits<T>::max();

  vector<T> dist(g.n, INF);
  dist[s] = 0;

  rep(i, g.n) rep(v, g.n) each(e, g[v]) {
    if (dist[v] == INF) continue;
    if (dist[e.to] <= dist[v] + e.cost) continue;
    dist[e.to] = dist[v] + e.cost;
    if (i == g.n - 1) {
      return vector<T>();
    }
  }

  return dist;
}

void solve() {
  int N, M, P;
  cin >> N >> M >> P;
  WeightedGraph<int> g(N);
  rep(i, M) {
    int a, b, c;
    cin >> a >> b >> c;
    a--, b--;
    g.add_edge(a, b, P - c);
  }
  vector<int> can(N);
  {
    vector<int> can1(N);
    vector<int> seen(N);
    auto dfs1 = [&](auto dfs1, int u) -> int {
      seen[u] = 1;
      if (u == N - 1) return 1;
      each(e, g[u]) {
        if (seen[e.to]) continue;
        if (dfs1(dfs1, e.to)) return 1;
      }
      return 0;
    };
    can1[N - 1] = 1;
    rep(i, N - 1) {
      seen.assign(N, 0);
      seen[i] = 1;
      can1[i] = dfs1(dfs1, i);
    }
    vector<int> can2(N);
    auto dfs2 = [&](auto dfs2, int u) -> void {
      can2[u] = 1;
      seen[u] = 1;
      each(e, g[u]) {
        if (seen[e.to]) continue;
        dfs2(dfs2, e.to);
      }
    };
    seen.assign(N, 0);
    dfs2(dfs2, 0);
    rep(i, N) if (can1[i] && can2[i]) can[i] = 1;
  }
  vector<int> ns;
  rep(i, N) if (can[i] == 1) ns.push_back(i);
  WeightedGraph<int> h(ns.size());
  rep(i, N) each(e, g[i]) {
    if (binary_search(all(ns), i) && binary_search(all(ns), e.to)) {
      int u = lower_bound(all(ns), i) - ns.begin();
      int v = lower_bound(all(ns), e.to) - ns.begin();
      h.add_edge(u, v, e.cost);
    }
  }
  auto res = bellman_ford(h, 0);
  if (res.size() == 0) {
    cout << -1 << endl;
  } else {
    cout << max(0, -res.back()) << endl;
  }
}


Measured memory_bytes: 640