#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433;

template <class T> vector<T> make_v(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto make_v(size_t N,T... t){return vector<decltype(make_v(t...))>(N,make_v(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}

int main() {
    ll N,M,Q; cin >> N >> M >> Q;
    vector<ll> cost(N,LOWINF),costL(N,1),costR(N,1);
    vector<ll> A(M),B(M),C(M);
    for(int i = 0; i < M; ++i){
        cin >> A[i] >> B[i] >> C[i];
        A[i]--,B[i]--;
    }
    cost[0] = 0;
    for(int i = 0; i < N; ++i){
        for(int j = 0; j < M; ++j){
            chmin(cost[B[j]],cost[A[j]] + Q - C[j]);  
        }
    }
    auto tmp = cost;
    for(int i = 0; i < N; ++i){
        for(int j = 0; j < M; ++j){
            chmin(tmp[B[j]],tmp[A[j]] + Q - C[j]);  
        }
    }
    costL[0] = 0;
    for(int i = 0; i < N; ++i){
        for(int j = 0; j < M; ++j){
            chmin(costL[B[j]],costL[A[j]]);  
        }
    }
    costR[N-1] = 0;
    for(int i = 0; i < N; ++i){
        for(int j = 0; j < M; ++j){
            chmin(costR[A[j]],costR[B[j]]);  
        }
    }
    
    for(int i = 0; i < N; ++i){
        if(tmp[i]<cost[i] && !costL[i] && !costR[i]) {
            cout << -1 << endl;
            return 0;
        }
    }
    cout << max(0LL,-cost[N-1]) << endl;

    return 0;
}


Measured memory_bytes: 512