#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; }

void solve() {
  int N, M, P;
  cin >> N >> M >> P;
  vector<tuple<int, int, int>> es;
  vector<vi32> to(N);
  vector<vi32> ot(N);
  rep(i, M) {
    int a, b, c;
    cin >> a >> b >> c;
    a--, b--;
    c = P - c;
    es.emplace_back(a, b, c);
    to[a].emplace_back(b);
    ot[b].emplace_back(a);
  }
  vector<bool> can(N);
  {
    vector<bool> can1(N);
    vector<bool> canN(N);
    auto dfs1 = [&](auto dfs1, int u) -> void {
      can1[u] = true;
      each(v, to[u]) if (!can1[v]) dfs1(dfs1, v);
    };
    auto dfsN = [&](auto dfsN, int u) -> void {
      canN[u] = true;
      each(v, ot[u]) if (!canN[v]) dfsN(dfsN, v);
    };
    dfs1(dfs1, 0);
    dfsN(dfsN, N - 1);
    rep(i, N) can[i] = can1[i] && canN[i];
  }
  vector<int> dist(N, 2e9);
  dist[0] = 0;
  rep(i, N) each(e, es) {
    int u, v, c;
    tie(u, v, c) = e;
    if (!can[u] || !can[v]) continue;
    if (dist[v] <= dist[u] + c) continue;
    if (i == N - 1) {
      cout << -1 << endl;
      return;
    }
    dist[v] = dist[u] + c;
  }
  cout << max(0, -dist[N - 1]) << endl;
}


Measured memory_bytes: 768