#ifdef _MSC_VER
#pragma warning(disable : 4996)
#include <intrin.h>
#define __builtin_popcount __popcnt
#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
#define int long long
//#define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v) REP(i, v.size()) cout << v[i] << ((i == v.size() - 1) ? "\n" : " ")
template <typename T1, typename T2> inline void chmin(T1& a, T2 b) {
	if (a > b) a = b;
}
template <typename T1, typename T2> inline void chmax(T1& a, T2 b) {
	if (a < b) a = b;
}
typedef pair<int, int> pii;
typedef array<int, 3> arr3;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 200020;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll INF = 1e16;

using Point = complex<double>;
typedef int Weight;
struct Edge {
	int src, dst;
	Weight weight;
	Edge(int src, int dst, Weight weight) :
		src(src), dst(dst), weight(weight) { }
};
bool operator < (const Edge &e, const Edge &f) {
	return e.weight != f.weight ? e.weight > f.weight : // !!INVERSE!!
	e.src != f.src ? e.src < f.src : e.dst < f.dst;
}
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

typedef vector<Weight> Array;
typedef vector<Array> Matrix;

bool vis[10010];
bool canreach[10010];
void dfs(int n, int pre, Graph &g) {
	vis[n] = true;
	canreach[n] = true;
	for (auto e : g[n]) {
		int nxt = e.dst;
		if (vis[nxt])continue;
		dfs(nxt, n, g);
	}
}

bool shortestPath(const Graph g, int s,
	vector<Weight> &dist, vector<int> &prev) {
	int n = g.size();
	dist.assign(n, INF + INF); dist[s] = 0;
	prev.assign(n, -2);
	bool negative_cycle = false;
	REP(k, 10*n) REP(i, n) for (auto e : g[i]) {
		if (!canreach[e.src])continue;
		if (dist[e.dst] > dist[e.src] + e.weight) {
			dist[e.dst] = dist[e.src] + e.weight;
			prev[e.dst] = e.src;
			if (k >= n - 1) {
				dist[e.dst] = -INF;
				negative_cycle = true;
			}
		}
	}
	return !negative_cycle;
}
vector<int> buildPath(const vector<int> &prev, int t) {
	vector<int> path;
	for (int u = t; u >= 0; u = prev[u])
		path.push_back(u);
	reverse(path.begin(), path.end());
	return path;
}


void solve() {
	int N, M, P; cin >> N >> M >> P;
	Graph g;
	g.resize(N);
	REP(i, M) {
		int u, v, c; cin >> u >> v >> c;
		c -= P;
		c = -c;
		u--, v--;
		g[u].push_back({ u,v,c });
	}
	dfs(0, 0, g);
	vector<int>dist, prev;
	bool ret = shortestPath(g, 0, dist, prev);
	if (dist[N - 1] == -INF) {
		cout << -1 << endl;
	}
	else cout << max(0LL, -dist[N - 1]) << endl;
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	// int q; cin >> q;
	// while (q--)
	solve();
}


Measured memory_bytes: 896