#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("YES")
#define p_no() p("NO")
#define pb(s) push_back(s)
#define SZ(x) ((int)(x).size())

const ll mod = 1e9 + 7;
const ll inf = 1e18;

void vprint(vector<ll> A){
    ll L = A.size();
    FOR(i, 0, L){
        if(i) cout << ' ';
        cout << A[i];
    }
    cout << endl;
}

struct Edge{
    ll to;
    ll cost;
    Edge(ll to, ll cost): to(to), cost(cost) {}
    Edge(){}
};
 
struct BellmanFord{
    vector<vector<Edge> > edges;
    vector<ll> dist;
    vector<bool> is_negative;
    ll N;
    bool is_negative_loop_exist = false;
     
    BellmanFord(ll sz){
        N = sz;
        edges.resize(N);
        dist.resize(N, inf);
        is_negative.resize(N, false);
    }
 
    void add_edge(ll a, ll b, ll c){
        edges[a].push_back(Edge(b, c));
    }


    void do_loop(ll loop){
        while(loop--){
            FOR(i, 0, N){
                if(dist[i]==inf) continue;
                for(auto edge : edges[i]){
                    chmin(dist[edge.to], dist[i] + edge.cost);
                }
            }
        }
    }
 
  // 計算量 V * E
  void calc_shortest_path(ll start){
      dist[start] = 0;
      do_loop(N);

      // negative check
      FOR(i, 0, N){
          if(dist[i]==inf) continue;

          for(auto edge : edges[i]){
              if(dist[i] + edge.cost < dist[edge.to]){
                  // まだ減るなら閉路
                  is_negative_loop_exist = true;

                  // 閉路フラグ
                  is_negative[edge.to] = true;
              }
          }
      }

      return;
  }
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N,M,P;cin>>N>>M>>P;

    auto bell = BellmanFord(N);

    rep(i, M){
      ll a,b,c;cin>>a>>b>>c;
      a--;
      b--;
      c -= P; // 時間を辺に含める
      c *= -1; // 最長距離問題を最短距離問題にする
      bell.add_edge(a, b, c);
    }

    bell.calc_shortest_path(0);
    if(!bell.is_negative_loop_exist){
      // 最短距離が見つかった
      ll ans = -bell.dist[N-1];
      ans = max(0LL, ans);
      p(ans);
      return 0;
    }

    // 負閉路を検出した
    if(bell.is_negative_loop_exist){

      ll d = bell.dist[N-1];
      rep(i, N){
        if(bell.is_negative[i]){
          bell.dist[i] = -inf;
        }
      }      
      bell.do_loop(N);
      ll d2 = bell.dist[N-1];

      if(d!=d2){
        // 負閉路の影響を受けている
        p(-1);
      }else{
        ll d = bell.dist[N-1];
        ll ans = -d;
        ans = max(0LL, ans);
        p(ans);
      }
    }

    return 0;
}

Measured memory_bytes: 512