#include <bits/stdc++.h>
#define ADD(a, b) a = (a + ll(b)) % mod
#define MUL(a, b) a = (a * ll(b)) % mod
#define MAX(a, b) a = max(a, b)
#define MIN(a, b) a = min(a, b)
#define rep(i, a, b) for(int i = int(a); i < int(b); i++)
#define rer(i, a, b) for(int i = int(a) - 1; i >= int(b); i--)
#define all(a) (a).begin(), (a).end()
#define sz(v) (int)(v).size()
#define pb push_back
#define sec second
#define fst first
#define debug(fmt, ...) Debug(__LINE__, ":", fmt, ##__VA_ARGS__)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<int, pi> ppi;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> mat;
typedef complex<double> comp;
void Debug() {cerr << '\n'; }
template<class FIRST, class... REST>void Debug(FIRST arg, REST... rest){
	cerr<<arg<<" ";Debug(rest...);}
template<class T>ostream& operator<<(ostream& out,const vector<T>& v) {
	out<<"[";if(!v.empty()){rep(i,0,sz(v)-1)out<<v[i]<<", ";out<<v.back();}out<<"]";return out;}
template<class S, class T>ostream& operator<<(ostream& out,const pair<S, T>& v){
	out<<"("<<v.first<<", "<<v.second<<")";return out;}
const int MAX_N = 500010;
const int MAX_V = 100010;
const double eps = 1e-6;
const ll mod = 1000000007;
const int inf = 1 << 30;
const ll linf = 1LL << 60;
const double PI = 3.14159265358979323846;
mt19937 rng; //use it by rng() % mod, shuffle(all(vec), rng)
///////////////////////////////////////////////////////////////////////////////////////////////////

struct edge {
	int to; ll cost;
};

int N, M, P;
vector<edge> E[2510];
vector<int> G[2510];
ll d[2510];
bool used[2510];


bool bellman_ford(int s) {
	//if a negative loop that can be reached from s exists, return true
	fill(d, d + N, linf);
	d[s] = 0;
	for(int k = 0; k < N; k++) {
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < sz(E[i]); j++) {
				edge e = E[i][j];
				if(d[i] != linf && d[e.to] > d[i] + e.cost) {
					d[e.to] = d[i] + e.cost;
					if(k >= N - 1 && used[e.to]) return true;
				}
			}
		}
	}
	return false;
}

void reachable(int s) {
	used[s] = true;
	queue<int> que;
	que.push(s);
	while(!que.empty()) {
		int v = que.front(); que.pop();
		rep(i, 0, sz(G[v])) {
			int n = G[v][i];
			if(!used[n]) {
				used[n] = true;
				que.push(n);
			}
		}
	}
}

void add_edge(int s, int t, ll cost) {//one way path
	E[s].push_back(edge{t, cost});
}


void solve() {
	cin >> N >> M >> P;
	rep(i, 0, M) {
		int a, b; ll c;
		cin >> a >> b >> c; a--; b--;
		add_edge(a, b, P - c);
		G[b].pb(a);
	}
	reachable(N - 1);
	if(bellman_ford(0)) {
		cout << -1 << "\n";
	}
	else cout << max(0ll, d[N - 1] * -1) << "\n";
}

uint32_t rd() {
	uint32_t res;
#ifdef __MINGW32__
	asm volatile("rdrand %0" :"=a"(res) ::"cc");
#else
	res = std::random_device()();
#endif
	return res;
}

int main() {
#ifndef LOCAL
	ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    cout << fixed;
	cout.precision(20);
    cerr << fixed;
	cerr.precision(6);
	rng.seed(rd());
#ifdef LOCAL
	//freopen("in.txt", "wt", stdout); //for tester
	if(!freopen("in.txt", "rt", stdin)) return 1;
#endif	
	solve();
    cerr << "Time: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
	return 0;
}



Measured memory_bytes: 640