#include <bits/stdc++.h>

using namespace std;

#define int long long
#define FOR(i, a, b) for(ll i = (a); i < (b); ++i)
#define FORR(i, a, b) for(ll i = (a); i > (b); --i)
#define REP(i, n) for(ll i = 0; i < (n); ++i)
#define REPR(i, n) for(ll i = n; i >= 0; i--)
#define FOREACH(x, a) for(auto &(x) : (a))
#define VECCIN(x)                                                              \
    for(auto &youso_ : (x)) cin >> youso_
#define bitcnt __builtin_popcount
#define SZ(x) ((ll)(x).size())
#define fi first
#define se second
#define All(a) (a).begin(), (a).end()
template <typename T = long long> inline T IN() {
    T x;
    cin >> x;
    return (x);
}
inline void CIN() {}
template <class Head, class... Tail>
inline void CIN(Head &&head, Tail &&... tail) {
    cin >> head;
    CIN(move(tail)...);
}
#define CINT(...)                                                              \
    int __VA_ARGS__;                                                           \
    CIN(__VA_ARGS__)
#define DCIN(...)                                                              \
    double __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define LCIN(...)                                                              \
    ll __VA_ARGS__;                                                            \
    CIN(__VA_ARGS__)
#define SCIN(...)                                                              \
    string __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define Yes(a) cout << (a ? "Yes" : "No") << "\n"
#define YES(a) cout << (a ? "YES" : "NO") << "\n"
#define Printv(v)                                                              \
    {                                                                          \
        FOREACH(x, v) { cout << x << " "; }                                    \
        cout << "\n";                                                          \
    }
template <typename T = string> inline void eputs(T s) {
    cout << s << "\n";
    exit(0);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *)array, (T *)(array + N), val);
}
template <typename T> using PQG = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using PQ = priority_queue<T>;

typedef long long ll;
typedef unsigned long long ul;
typedef vector<ll> VL;
typedef pair<ll, ll> PL;

const int INF = 1e9;
const int MOD = 1e9 + 7;
const double PI = atan(1.0) * 4.0;
// const int MOD = 998244353;
const ll LINF = 9e18;
const ll dx[] = {1, 0, -1, 0};
const ll dy[] = {0, 1, 0, -1};

struct edge {
    ll from, to, cost;
    bool operator<(const edge &another) const { return cost < another.cost; };
    bool operator>(const edge &another) const { return cost > another.cost; };
};
ll N, M, P;
vector<edge> es;
VL d;

bool find_nloop(ll s) {
    d.assign(N, LINF);
    d[s] = 0;
    ll cnt = 0;
    while(true) {
        bool update = false, update2 = false;
        REP(i, SZ(es)) {
            edge e = es[i];
            if(d[e.from] != LINF && d[e.to] > d[e.from] + e.cost) {
                d[e.to] = d[e.from] + e.cost;
                update = true;
                if(e.to == N - 1) update2 = true;
            }
        }
        cnt++;
        if(!update) break;
        if(cnt >= 2*N && update2) return true;
        if(cnt == 3 * N) return false;
    }
    return false;
}
void berman(ll s) {
    d.assign(N, LINF);
    d[s] = 0;
    ll cnt = 0;
    while(true) {
        bool update = false;
        REP(i, SZ(es)) {
            edge e = es[i];
            if(d[e.from] != LINF && d[e.to] > d[e.from] + e.cost) {
                d[e.to] = d[e.from] + e.cost;
                update = true;
            }
        }
        cnt++;
        if(!update) break;
        if(cnt == 3 * N) break;
    }
}

signed main() {
    cin >> N >> M >> P;
    REP(i, M) {
        LCIN(A, B, C);
        es.push_back({--A, --B, -C + P});
    }
    if(find_nloop(0)) {
        eputs(-1);
    } else {
        berman(0);
        cout << max(-d[N - 1], 0LL) << "\n";
    }
}

Measured memory_bytes: 512