#include <bits/stdc++.h>
#define range(i, l, r) for(int (i) = (l); (i) < (r); (i)++)
#define reversed_range(i, l, r) for (int (i) = (r) - 1; (i) >= l; (i)--)
using namespace std;
template <typename T>
using vec = vector<T>;
using lint = long long;
using ulint = unsigned long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;

template <typename S, typename T>
ostream& operator <<(ostream& os, pair<S, T> p) {
    os << "(";
    os << p.first << ", " << p.second;
    return os << ")";
}

template <typename T>
ostream& operator <<(ostream& os, vec<T> v) {
    os << "[";
    if (v.size() == 0) return os << "]";
    for (int i = 0; i < v.size() - 1; i++) {
        os << v.at(i) << ", ";
    }
    return os << v.at(v.size() - 1) << "]";
}

template <typename T>
ostream& operator <<(ostream& os, set<T>& s) {
    os << "{";
    if (s.begin() == s.end()) return os << "}";
    auto it_first_item = s.begin();
    cout << *it_first_item;
    for (auto it = ++it_first_item; it != s.end(); it++) {
        cout << ", " << *it;
    }
    return cout << "}";
}

template <typename T>
ostream& operator <<(ostream& os, unordered_set<T>& s) {
    os << "{";
    if (s.begin() == s.end()) return os << "}";
    auto it_first_item = s.begin();
    cout << *it_first_item;
    for (auto it = ++it_first_item; it != s.end(); it++) {
        cout << ", " << *it;
    }
    return cout << "}";
}

template <typename K, typename V>
ostream& operator <<(ostream& os, map<K, V> m) {
    os << "{";
    if (m.begin() == m.end()) return os << "}";
    auto it_first_item = m.begin();
    cout << it_first_item->first << ": " << it_first_item->second;
    for (auto it = ++it_first_item; it != m.end(); it++) {
        cout << ", " << it->first << ": " << it->second;
    }
    return os << "}";
}

template <typename K, typename V>
ostream& operator <<(ostream& os, unordered_map<K, V> m) {
    os << "{";
    if (m.begin() == m.end()) return os << "}";
    auto it_first_item = m.begin();
    cout << it_first_item->first << ": " << it_first_item->second;
    for (auto it = ++it_first_item; it != m.end(); it++) {
        cout << ", " << it->first << ": " << it->second;
    }
    return os << "}";
}

lint pow(lint num, lint e, lint MOD) {
    lint res = 1;
    lint cur_num = num;
    while (e) {
        if (e & 1) {
            res *= cur_num;
            res %= MOD;
        }
        cur_num *= cur_num;
        cur_num %= MOD;
        e >>= 1;
    }
    return res;
}

int main() {
    cin.tie(0); cout.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    lint N, M, P;
    cin >> N >> M >> P;
    vec<vec<lint>> adj(N, vec<lint>()), rev_adj(N, vec<lint>());
    vec<vec<lint>> edges(M);
    range(i, 0, M) {
        lint A, B, C;
        cin >> A >> B >> C;
        A--; B--;
        adj.at(A).emplace_back(B);
        rev_adj.at(B).emplace_back(A);
        edges.at(i) = {A, B, -C + P};
    }

    auto reachable_nodes = [](lint s, const vec<vec<lint>>& adj) {
        lint N = adj.size();
        vec<bool> visited(N, false);
        visited.at(s) = true;
        vec<lint> nodes_in_process = {s};
        while (nodes_in_process.size() != 0) {
            lint node = nodes_in_process.back();
            nodes_in_process.pop_back();
            for (const auto neighbor : adj.at(node)) {
                if (!visited.at(neighbor)) {
                    visited.at(neighbor) = true;
                    nodes_in_process.emplace_back(neighbor);
                }
            }
        }
        return visited;
    };

    const vec<bool>& reachable_from_s = reachable_nodes(0, adj);
    const vec<bool>& reachable_to_t = reachable_nodes(N - 1, rev_adj);
    // cout << reachable_from_s << "\n";
    // cout << reachable_to_t << "\n";
    auto bellman_ford = [&](lint s) {
        vec<lint> d(N, 1LL << 58);
        d.at(s) = 0;
        range(_, 0, N) {
            for (const auto e : edges) {
                lint u = e.at(0), v = e.at(1), c = e.at(2);
                if (d.at(v) > d.at(u) + c) {
                    d.at(v) = d.at(u) + c;
                }
            }
        }
        for (const auto e : edges) {
            lint u = e.at(0), v = e.at(1), c = e.at(2);
            if (reachable_from_s.at(u) and reachable_to_t.at(u)
            and reachable_from_s.at(v) and reachable_to_t.at(v)
            and d.at(v) > d.at(u) + c) return -1LL;
        }
        return max(0LL, -d.at(N - 1));
    };
    lint profit = bellman_ford(0);
    cout << profit << "\n";
}


Measured memory_bytes: 896