#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <stack>
#include <queue>
#include <bitset>
#include <numeric>
#include <cassert>
#include <array>
#include <memory>
#include <random>
#include <functional>
#include <complex>
#ifdef DEBUG
#include "./Lib/debug.hpp"
#include "./Lib/Timer.hpp"
#include "./Lib/sample.hpp"
#else
#define dump(...)
#endif

/* (=＾o＾=) */
//#define int ll

/* macro */
#define FOR(i, b, e) for(ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for(ll i = (ll)(e-1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x,c) for(const auto& x:(c))
#define REPI2(it,b,e) for(auto it = (b); it != (e); ++it)
#define REPI(it,c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it,c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for(auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(),(x).end()
#define cauto const auto&
/* macro func */
template<class T>
inline void sort(T& t) { std::sort(ALL(t)); }
template<class T>
inline void rsort(T& t) { std::sort((t).rbegin(), (t).rend()); }
template<class T>
inline void unique(T& t) { (t).erase(unique((t).begin(), (t).end()), (t).end()); }
template<class T, class S>
inline bool chmax(T& t, const S& s) { if (s > t) { t = s; return true; } return false; }
template<class T, class S>
inline bool chmaxE(T& t, const S& s) { if (s >= t) { t = s; return true; } return false; }
template<class T, class S>
inline bool chmin(T& t, const S& s) { if (s < t) { t = s; return true; } return false; }
inline void BR() { std::cout << "\n"; }

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template<class T>
using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\n';
using std::cin;
using std::pair;
using std::string;
using std::stack;
using std::queue;
using std::vector;
using std::list;
using std::map;
using std::unordered_map;
using std::multimap;
using std::unordered_multimap;
using std::set;
using std::unordered_set;
using std::unordered_multiset;
using std::multiset;
using std::bitset;
using std::priority_queue;
using std::tuple;

/* Initial processing  */
struct Preprocessing { Preprocessing() { std::cin.tie(0); std::ios::sync_with_stdio(0); }; }_Preprocessing;

/* Remove the source of the bug */
inline signed pow(signed, signed) { assert(false); return -1; }

/* define hash */
namespace std {
template <>	class hash<std::pair<ll, ll>> { public:	size_t operator()(const std::pair<ll, ll>& x) const { return hash<ll>()(1000000000 * x.first + x.second); } };
}

/* input */
template<class T> std::istream& operator >> (std::istream& is, vector<T>& vec) { for (T& x : vec) is >> x; return is; }

/* constant value */
constexpr ll MOD = 1000000007;
//constexpr ll MOD = 998244353;
//constexpr ll MOD = 2;

//=============================================================================================


VL BellmanFord(const unordered_multimap<ll, PAIR> graph, ll n, ll begin) {
	VL cost(n, 1e15);
	cost[begin] = 0;

	REP(_, graph.size()) REP(from, n) {
		auto range = graph.equal_range(from);
		REPI2(itr, range.first, range.second) {
			ll to = itr->second.first;
			ll c = itr->second.second;
			cost[to] = std::min(cost[to], cost[from] + c);
		}
	}

	V<bool> non(n, true);
	non[0] = false;
	queue<ll> q;
	q.emplace(0);
	while (!q.empty()) {
		auto from = q.front();
		q.pop();

		auto range = graph.equal_range(from);
		REPI2(itr, range.first, range.second) {
			auto to = itr->second.first;
			if (non[to]) {
				q.emplace(to);
				non[to] = false;
			}
		}
	}

	dump(graph);
	dump(cost, non);
	VL cost_ = cost;
	REP(_, n + 100)REP(from, n) {
		auto range = graph.equal_range(from);
		if (non[from]) { continue; }
		REPI2(itr, range.first, range.second) {
			ll to = itr->second.first;
			ll c = itr->second.second;
			if (cost_[from] > 1e14) {
				cost_[to] = 1e15;
			} else if (cost[from] + c < cost[to]) {
				cost[to] = cost[from] + c;
				cost_[to] = 1e15;
			}
		}
	}
	return cost_;
}


signed main() {
	ll n, m, p;
	cin >> n >> m >> p;
	unordered_multimap<ll, PAIR> graph;
	REP(_, m) {
		ll a, b, c;
		cin >> a >> b >> c;
		--a; --b;
		graph.emplace(a, PAIR{b,-c + p});
	}

	auto min = BellmanFord(graph, n, 0);
	dump(min);
	if (min[n - 1] > 1e14) { cout << -1 << endl; return 0; }

	cout << std::max(-min[n - 1], 0LL) << endl;
}



Measured memory_bytes: 1024