#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
inline ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
inline ll lcm(ll a, ll b) { return a / gcd(a, b)*b; }
template<class S,class T> ostream& operator << (ostream& out,const pair<S,T>& o){ out << "(" << o.first << "," << o.second << ")"; return out; }
template<class T> ostream& operator << (ostream& out,const vector<T>& V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; }
template<class T> ostream& operator << (ostream& out,const vector<vector<T> >& Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; }
template<class S,class T> ostream& operator << (ostream& out,const map<S,T>& mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; }
template<typename T>vector<T> make_v(size_t a){return vector<T>(a);}
template<typename T,typename... Ts>auto make_v(size_t a,Ts... ts){return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type fill_v(T &t,const V &v){t=v;}
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type fill_v(T &t,const V &v){for(auto &e:t) fill_v(e,v);}
/*
 <url:https://atcoder.jp/contests/abc137/tasks/abc137_e>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */

template<class Type>
Type solve(Type res = Type()){
    int N,M; cin >> N >> M;
    
    vector<vector<pll>> G(N);
    vector<vector<ll>> rG(N);
    
    ll P; cin >> P;
    for(int i = 0; i < M;i++){
        int A,B; cin >> A >> B;
        ll C; cin >> C;
        
        A--;B--;
        G[A].emplace_back(B,-(C-P));
        rG[B].emplace_back(A);
    }
        vector<bool> can_visit_to_Zero(N);
    function<void(int)> rec1 = [&](int n){
        if(can_visit_to_Zero[n]) return;
        can_visit_to_Zero[n] = true;
        for(auto next:G[n]) rec1((int)next.first);
    };
    rec1(0);
    vector<bool> can_visit_to_N(N);
    function<void(int)> rec2 = [&](int n){
        if(can_visit_to_N[n]) return;
        can_visit_to_N[n] = true;
        for(auto next:rG[n]) rec2((int)next);
    };
    rec2(N-1);
    
    // bellman ford
    vector<ll> dist(N,LINF);
    dist[0] = 0;
    auto ok = [&](){
        for(int i = 0; i < N;i++){
            bool update = true;
            for(int v = 0; v < N;v++){
                for(int j = 0; j < (int)G[v].size();j++){
                    ll next,cost; tie(next,cost) = G[v][j];
                    if(can_visit_to_N[next] && can_visit_to_Zero[next] && dist[next] > dist[v] + cost){
                        dist[next] = dist[v] + cost;
                        update = false;
                        if(i == N-1) return true;
                    }
                }
            }
            if(update) return false;
        }
        return false;
    }();
    
    if(ok) res = -1;
    else res = max(0LL,-dist[N-1]);
    return res;
}
int main(void) {
    cin.tie(0); ios_base::sync_with_stdio(false);
    // solve(0);
    cout << fixed << setprecision(15) << solve<ll>() << endl;
    return 0;
}


Measured memory_bytes: 640