#include <bits/stdc++.h>
#include <functional>
#include <iomanip>
using namespace std;
	
#define int long long
#define pb push_back
#define ub upper_bound
#define lb upper_bound
#define mp make_pair
#define F first
#define S second
#define FOR(i,a,b) for(int (i)=(a);(i)<(b);(i)++)
#define REP(i,n) FOR(i,0,n)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define SORT(c) sort((c).begin(),(c).end())
#define ve vector
#define vi vector<int>
#define vp vector<pair<int,int>>
#define vvi vector<vector<int>>

using ll = long long;
ll INF = LLONG_MAX / 4 - 100;
ll mod = 1e9 + 7;
int dx[] = {-1,0,1,0}, dy[] = {0,1,0,-1};
vector<ll> prime;
	
class fact {
public:
	int fmod = 1e9+7;
	vector<int> fac, inv;
	fact (int n, int Mod = 1e9+7) {
		fmod = Mod;
		fac = vector<int>(n,0);
		inv = vector<int>(n,0);
		fac[0] = 1; for (int i = 1; i < n; i++) fac[i] = fac[i-1] * i % fmod;
		for (int i = 0;i < n;i++) inv[i] = fact::POW(fac[i],fmod-2);
	}
	ll nCr(ll n, ll r) {return (fac[n] * inv[r] % fmod) * inv[n-r] % fmod;}
	ll POW(ll a, ll b) {ll c = 1; while (b > 0) {if (b & 1) {c = a * c%fmod;}a = a * a%fmod; b >>= 1;}return c;}
};
	
template <class T = ll> T in() {T x; cin >> x; return (x);}
void DEBUG(vector<int> a) {for(int i=0;i<a.size();i++)cout<<a[i]<<" ";cout<<endl;}
void EMP(int x) {cout<<"!!!"<<x<<"!!!"<<endl;}
ll GCD(ll a, ll b) {ll c; while (b != 0) {c = a % b; a = b; b = c;}return a;}
ll LCM(ll a, ll b) {return a * b / GCD(a, b);}
ll POW(ll a, ll b) {ll c = 1; while (b > 0) {if (b & 1) {c = a * c%mod;}a = a * a%mod; b >>= 1;}return c;}
void PRI(ll n) {bool a[n + 1LL]; for (int i = 0; i < n + 1LL; i++) {a[i] = 1LL;}for (int i = 2; i < n + 1LL; i++) {if (a[i]) {prime.pb(i); ll b = i; while (b <= n) {a[b] = 0; b += i;}}}}
template <typename T> T chmin(T& a, T b) {if(a>b)a=b;return a;}
template <typename T> T chmax(T& a, T b) {if(a<b)a=b;return b;}
bool isSqrt(ll a) {return pow(sqrt(a),2) == a ? 1 : 0;}
void YesNo(bool a) {if (a) cout << "Yes"; else cout << "No"; cout << endl;}
void yesno(bool a) {if (a) cout << "yes"; else cout << "no"; cout << endl;}
void YESNO(bool a) {if (a) cout << "YES"; else cout << "NO"; cout << endl;}
double dis(int x1, int x2, int y1, int y2) {
    return sqrt((double)abs(x1-x2)*(double)abs(x1-x2)+(double)abs(y1-y2)*(double)abs(y1-y2));
}

int cost[2550][2550];
int poin[2550];


typedef struct {
    int from;
    int to;
    int cost;
} Edge;
 
class BellemanFord {
public:
    vector<Edge> edge;
    vector<ll> dist;
    bool bellemanford(int v,int s) {
        dist = vector<ll>(v,INF);
        dist[s] = 0;
        for (int i = 0;i < v*3;i++) {
            for (int j = 0;j < edge.size();j++) {
                if (dist[edge[j].from] + edge[j].cost < dist[edge[j].to]) {
                    if (dist[v-1] < -INF/2) return true;
                    dist[edge[j].to] = dist[edge[j].from] + edge[j].cost;
                    if (i >= v-1 && edge[j].to == v-1) return true;
                }
            }
        }
        return false;
    }
};


bool solve() {
    // REP (i,2550) REP (j,2550) cost[i][j] = INF;
    BellemanFord bf;
    // int n,m; cin >> n >> m;
    // vector<pair<int,int>> ab(n);
    // REP (i,n) cin >> ab[i].F >> ab[i].S;
    // set<pair<int,int>> get;
    // REP (i,n) get.insert(ab[i].S);
    // sort(all(ab)); reverse(all(ab));
    // int day = 0;
    // int ans = 0;
    // bool rem[n]; REP (i,n) rem[i] = true;
    // int now = 0;
    // REP (i,m+1) {
    //     while(m-ab[now].F < i) get.erase(ab[now].S),now++;
    //     if (get.size() == 0) break;
    //     ans += *get.rbegin();
    //     int tmp = *get.rbegin();
    //     cout << tmp << endl;
    //     get.erase(tmp);
    // }
    // cout << ans << endl;
    int n,m,p; cin >> n >> m >> p;
    REP (i,m) {
        int a,b,c; cin >> a >> b >> c;
        bf.edge.pb({--a,--b,-(c-p)});
    }
    if (bf.bellemanford(n,0)) {
        cout << -1 << endl;
    } else {
        cout << max(-bf.dist[n-1],0ll) << endl;
    }
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	solve();
}


Measured memory_bytes: 704