#include <bits/stdc++.h>
#include <cassert>
typedef long long int ll;
using namespace std;

// @@ !! LIM(debug)
// --> f:<< debug
// ---- inserted function << from util.cc
template <typename T1, typename T2>
ostream& operator<< (ostream& os, const pair<T1,T2>& p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}

template <typename T1, typename T2, typename T3>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3>& t) {
  os << "(" << get<0>(t) << ", " << get<1>(t)
     << ", " << get<2>(t) << ")";
  return os;
}

template <typename T1, typename T2, typename T3, typename T4>
ostream& operator<< (ostream& os, const tuple<T1,T2,T3,T4>& t) {
  os << "(" << get<0>(t) << ", " << get<1>(t)
     << ", " << get<2>(t) << ", " << get<3>(t) << ")";
  return os;
}

template <typename T>
ostream& operator<< (ostream& os, const vector<T>& v) {
  os << '[';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << ']';

  return os;
}

template <typename T>
ostream& operator<< (ostream& os, const set<T>& v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T>
ostream& operator<< (ostream& os, const multiset<T>& v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  os << '}';

  return os;
}

template <typename T1, typename T2>
ostream& operator<< (ostream& os, const map<T1, T2>& mp) {
  os << '[';
  for (auto it = mp.begin(); it != mp.end(); it++) {
    if (it != mp.begin()) os << ", ";
    os << it->first << ": " << it->second;
  }
  os << ']';

  return os;
}

template <typename T, typename T2>
ostream& operator<< (ostream& os, const queue<T, T2>& orig) {
  queue<T, T2> que(orig);
  bool first = true;
  os << '[';
  while (!que.empty()) {
    T x = que.front(); que.pop();
    if (!first) os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T, typename T2, typename T3>
ostream& operator<< (ostream& os, const priority_queue<T, T2, T3>& orig) {
  priority_queue<T, T2, T3> pq(orig);
  bool first = true;
  os << '[';
  while (!pq.empty()) {
    T x = pq.top(); pq.pop();
    if (!first) os << ", ";
    os << x;
    first = false;
  }
  return os << ']';
}

template <typename T>
ostream& operator<< (ostream& os, const stack<T>& st) {
  stack<T> tmp(st);
  os << '[';
  bool first = true;
  while (!tmp.empty()) {
    T& t = tmp.top();
    if (first) first = false;
    else os << ", ";
    os << t;
    tmp.pop();
  }
  os << ']';
  return os;
}

#if __cplusplus >= 201703L
template <typename T>
ostream& operator<< (ostream& os, const optional<T>& t) {
  if (t.has_value()) os << "v(" << t.value() << ")";
  else               os << "nullopt";
  return os;
}
#endif

// ---- end <<
// ---- inserted library file debug.cc
template <class... Args>
string dbgFormat(const char* fmt, Args... args) {
  size_t len = snprintf(nullptr, 0, fmt, args...);
  char buf[len + 1];
  snprintf(buf, len + 1, fmt, args...);
  return string(buf);
}

template <class Head>
void dbgLog(Head&& head) {
  cerr << head << endl;
}

template <class Head, class... Tail>
void dbgLog(Head&& head, Tail&&... tail)
{
  cerr << head << " ";
  dbgLog(forward<Tail>(tail)...);
}

#if DEBUG
  #define DLOG(...)        dbgLog(__VA_ARGS__)
  #define DFMT(...)        cerr << dbgFormat(__VA_ARGS__) << endl
  #define DCALL(func, ...) func(__VA_ARGS__)
#else
  #define DLOG(...)
  #define DFMT(...)
  #define DCALL(func, ...)
#endif

#if DEBUG_LIB
  #define DLOG_LIB(...)        dbgLog(__VA_ARGS__)
  #define DFMT_LIB(...)        cerr << dbgFormat(__VA_ARGS__) << endl
  #define DCALL_LIB(func, ...) func(__VA_ARGS__)
#else
  #define DLOG_LIB(...)
  #define DFMT_LIB(...)
  #define DCALL_LIB(func, ...)
#endif

// ---- end debug.cc
// @@ !! LIM  -- end mark --

struct MyExc : exception {};


int main(int argc, char *argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << setprecision(20);

  ll N, M, P; cin >> N >> M >> P;
  vector<ll> A(M), B(M), C(M);
  vector<vector<ll>> nbr(N), rev(N);
  vector<bool> reachN(N), reachR(N);
  for (ll i = 0; i < M; i++) {
    ll a, b, c; cin >> a >> b >> c; a--; b--;
    A.at(i) = a;
    B.at(i) = b;
    C.at(i) = c - P;
    nbr.at(a).push_back(b);
    rev.at(b).push_back(a);
  }
  auto dfs = [&](const auto& rF, const auto& dir, auto& rch, ll i) {
    if (rch.at(i)) return;
    rch.at(i) = true;
    for (ll x : dir.at(i)) rF(rF, dir, rch, x);
  };
  auto eff = [&](ll i) -> bool { return reachN.at(i) && reachR.at(i); };
  dfs(dfs, nbr, reachN, 0);
  dfs(dfs, rev, reachR, N-1);

  DLOG("reachN", reachN);
  DLOG("reachR", reachR);

  vector<optional<ll>> vec(N);
  vec.at(0) = 0;
  for (ll q = 0; q < N; q++) {
    bool changed = false;
    for (ll i = 0; i < M; i++) {
      ll a = A.at(i);
      ll b = B.at(i);
      auto& va = vec.at(a);
      auto& vb = vec.at(b);
      if (!eff(a) || !eff(b) || !va.has_value()) continue;
      ll x = va.value() + C.at(i);
      if (!vb.has_value() || x > vb.value()) {
	vb = x;
	changed = true;
      }
    }
    if (!changed) {
      cout << max(0LL, vec.at(N-1).value()) << endl;
      return 0;
    }
  }
  cout << -1 << endl;

  return 0;
}



Measured memory_bytes: 4136