// template version 1.12
using namespace std;
#include <iostream>
#include <bits/stdc++.h>

// varibable settings
#define infile "../test/sample-1.in"
#define int long long //{{{
const int INF=1e18;
const int MOD=1e9+7; //}}}

// define basic macro {{{
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define _rrep(i,n) rrepi(i,0,n)
#define rrepi(i,a,b) for(int i=(int)((b)-1);i>=(int)(a);--i)
#define rrep(...) _overload3(__VA_ARGS__,rrepi,_rrep,)(__VA_ARGS__)
#define each(i,a) for (auto&& i : a)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define uni(x) sort(all(x));x.erase(unique(all(x)),x.end())
#define ub upper_bound
#define lb lower_bound
#define posl(A, x) (lower_bound(all(A), x)-A.begin())
#define posu(A, x) (upper_bound(all(A),x)-A.begin())
template<class T> inline void chmax(T &a, const T &b) { if((a) < (b)) (a) = (b); }
template<class T> inline void chmin(T &a, const T &b) { if((a) > (b)) (a) = (b); }

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef long double ld;
typedef pair<int,int> pii;
typedef tuple<int,int,int> iii;

template<typename T> using PQ = priority_queue<T, vector<T>, greater<T>>;
struct Fast { Fast(){ std::cin.tie(0); ios::sync_with_stdio(false); } } fast;

#if defined(PCM) || defined(LOCAL)
  #include "lib/dump.hpp"
#else
  #define dump(...) 42
  #define dump_1d(...) 42
  #define dump_2d(...) 42
#endif
//}}}

// 隣接リストで使う辺を表す型
struct Edge {
  int to, cost;  // 辺の接続先頂点, 辺の重み
  Edge(int to, int cost) : to(to), cost(cost) {}  // コンストラクタ
};

typedef vector<vector<Edge> > AdjList;  // 隣接リストの型
AdjList graph;  // グラフの辺を格納した構造体
                // graph[v][i]は頂点vから出るi番目の辺Edge

vector<int> dist; // 最短距離

// 戻り値がtrueなら負の閉路を含む
bool bellman_ford(int n, int s) { // nは頂点数、sは開始頂点
  dist = vector<int>(n, INF);
  dist[s] = 0; // 開始点の距離は0

  for (int i = 0; i < 2*n; i++) {
    for (int v = 0; v < n; v++) {
      for (int k = 0; k < sz(graph[v]); k++) {
        Edge e = graph[v][k];
        if (dist[v] != INF && dist[e.to] > dist[v] + e.cost) {
          dist[e.to] = dist[v] + e.cost;
        }
      }
    }
  }
  int pre = dist[n-1];

  for (int i = 0; i < 2*n; i++) {
    for (int v = 0; v < n; v++) {
      for (int k = 0; k < sz(graph[v]); k++) {
        Edge e = graph[v][k];
        if (dist[v] != INF && dist[e.to] > dist[v] + e.cost) {
          dist[e.to] = dist[v] + e.cost;
        }
      }
    }
  }
  int after = dist[n-1];
  if (pre!=after){
    return true;
  }
  else{
    return false;
  }
}
int solve(){
  int n,m,p;cin>>n>>m>>p;
  graph = AdjList(n);
  dump(n,m,p);
  
  for (int i = 0; i < m; i++) {
    int from, to, cost;
    cin >> from >> to >> cost;
    from--;to--;
    cost = -(cost-p);
    dump(from, to, cost);
    graph[from].push_back(Edge(to, cost));
  }
  
  bool inf = bellman_ford(n, 0LL);
  if (inf==true){
    cout << -1 << endl;
    return 0;
  }
  dump(dist);
  
  cout << max(0LL, -dist[n-1]) << endl;
  return 0;
}

signed main() { //{{{
#ifdef INPUT_FROM_FILE
  std::ifstream in(infile);
  std::cin.rdbuf(in.rdbuf());
#endif
  solve();
  return 0;
} //}}}


Measured memory_bytes: 512