// #define DEBUGGING
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()

template <typename T> using V = vector<T>;
template <typename T> using VV = V<V<T>>;
using ll = int64_t;
using ull = uint64_t;
using PLL = pair<ll, ll>;

template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> const T& clamp(const T &t, const T &low, const T &high) { return max(low, min(high, t)); }
template <typename T> void chclamp(T &t, const T &low, const T &high) { t = clamp(t, low, high); }

namespace init__ {

struct InitIO {
    InitIO() {
        cin.tie(nullptr);
        ios_base::sync_with_stdio(false);
        cout << fixed << setprecision(30);
    }
} init_io;

}

#ifdef DEBUGGING
// #include "../debug/debug.cpp"
#include "../../debug/debug.cpp"
#else
#define DEBUG(...) 0
#define DEBUG_SEPARATOR_LINE 0
#endif

template <typename T>
T make_v(T init) { return init; }

template <typename T, typename... Tail>
auto make_v(T init, size_t s, Tail... tail) {
#define rec make_v(init, tail...)
    return V<decltype(rec)>(s, rec);
#undef rec
}

const ll inf = 5e15;

VV<bool> can_go(const VV<PLL> &edges) {
    auto ret = make_v(false, edges.size(), edges.size());
    auto bfs = [&](ll start) {
        queue<ll> que;
        que.push(start);
        ret[start][start] = true;
        while(que.size()) {
            ll cur = que.front();
            que.pop();
            for(auto &&edge : edges[cur]) {
                ll nxt, cost;
                tie(nxt, cost) = edge;
                if(ret[cur][nxt]) continue;
                ret[cur][nxt] = true;
                que.push(nxt);
            }
        }
    };
    for(ll start = 0; start < edges.size(); start++) bfs(start);
    return ret;
}

ll bell(const VV<PLL> &edges, ll start, ll goal) {
    V<ll> dists(edges.size(), inf);
    auto reaches = can_go(edges);
    ll node_size = edges.size();
    ll loop_upper = 5 * node_size;
    dists[start] = 0;
    for(ll loop = 1; loop <= loop_upper; loop++) {
        bool update = false;
        for(ll cur = 0; cur < node_size; cur++) {
            if(dists[cur] == inf) continue;
            for(auto &&edge : edges[cur]) {
                ll nxt, cost;
                tie(nxt, cost) = edge;
                if(dists[nxt] <= dists[cur] + cost) continue;
                if(reaches[nxt][goal]) {
                    DEBUG(nxt);
                    update = true;
                }
                dists[nxt] = dists[cur] + cost;
            }
        }
        if(update && node_size <= loop) return inf;
    }
    return -dists[goal];
}

int main() {
    ll N, M, P;
    cin >> N >> M >> P;
    VV<PLL> edges(N);
    while(M--) {
        ll a, b, c;
        cin >> a >> b >> c;
        edges[a - 1].emplace_back(b - 1, -(c - P));
    }
    auto res = bell(edges, 0, N - 1);
    cout << (res == inf ? -1ll : max<ll>(0, res)) << endl;
    return 0;
}


Measured memory_bytes: 1408