#ifdef DEBUG_IS_VALID
#define DEB 1 
#define _LIBCPP_DEBUG 0
#else
#define DEB 0
#define NDEBUG
#endif

#include <bits/stdc++.h>
using namespace std;

#define ALL(g) (g).begin(),(g).end()
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define RREP(i, x, n) for(int i = x; i >= n; i--)
#define rrep(i, n) RREP(i,n,0)
#define pb push_back
#define fi first
#define se second
#pragma GCC optimize ("-O3")

using namespace std;

#define DUMPOUT cout
#define dump(...) if(DEB) DUMPOUT<<"  "<<#__VA_ARGS__<<" :["<<__LINE__<<":"<<__FUNCTION__<<"]"<<endl<<"    "; if(DEB) dump_func(__VA_ARGS__)
template<typename T1,typename T2>ostream& operator << (ostream& os, pair<T1,T2> p){cout << "(" << p.first << ", " << p.second << ")"; return os;}
template<typename T>ostream& operator << (ostream& os, vector<T>& vec) { os << "{"; for (int i = 0; i<vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : ", "); os << "}"; return os; }
template<typename T>ostream& operator << (ostream& os, set<T>& st){cout << "{"; for(auto itr = st.begin(); itr != st.end(); itr++) cout << *itr << (next(itr)!=st.end() ? ", " : ""); cout << "}"; return os;}
template<typename T1,typename T2>ostream& operator << (ostream& os, map<T1,T2> mp){cout << "{"; for(auto itr = mp.begin(); itr != mp.end(); itr++) cout << "(" << (itr->first) << ", " << (itr->second) << ")" << (next(itr)!=mp.end() ? "," : ""); cout << "}"; return os; }

void dump_func(){DUMPOUT << endl;}
template <class Head, class... Tail>void dump_func(Head&& head, Tail&&... tail){ DUMPOUT << head; if (sizeof...(Tail) == 0) { DUMPOUT << " "; } else { DUMPOUT << ", "; } dump_func(std::move(tail)...);}
template<class T> inline bool chmax(T& a,T const& b){if(a>=b) return false; a=b; return true;}
template<class T> inline bool chmin(T& a,T const& b){if(a<=b) return false; a=b; return true;}

using ll = long long;
using P = pair<int,int>;
using Pl = pair<ll,ll>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vp = vector<Pl>;
using vvp = vector<vp>;

const int INF = 1<<29;
const long long LINF=1LL<<59;

vector<bool> reachable_from(const vector<vector<int>>& g, int from){
  // 有向グラフg上でfromから到達するかを返す
  int N = g.size();
  vector<bool> pass(N,false);
  function<void(int)> dfs = [&](int u){
    pass[u] = true;
    for(auto& v:g[u]) if(!pass[v]) dfs(v);
  };
  dfs(from);
  return pass;
}

vector<bool> reachable_to(const vector<vector<int>>& g, int target){
  // 有向グラフg上でtargetに到達するかを返す
  int N = g.size();
  vector<vector<int>> rev(N);
  for(int u = 0; u < N; u++)
    for(auto v:g[u]) rev[v].push_back(u);
  return reachable_from(rev, target);
}

using Cost = ll;
using Node = int;
struct Edge{
  Cost cost; Node to;
  Edge(Cost cost,Node to)
    :cost(cost),to(to){}
};
ostream& operator << (ostream& os, const Edge& e){
  cout << "{" << e.cost << ", " << e.to <<  "}"; return os;
}
using Graph = vector<vector<Edge>>;
struct BellmanFord{
  bool minus_cycle = false;
  vector<long long> dist;
  int cnt, N;
  BellmanFord(const Graph& graph, Node start = 0)
  :cnt(0), N(graph.size()), dist(graph.size(),LINF){
    dist[start] = 0;
    while(cnt < N){
      bool update = false;
      for(int i = 0; i < N; i++){
        for(auto&& e:graph[i]){
          if((dist[i] + e.cost < dist[e.to])){
            dist[e.to] = dist[i] + e.cost;
            update = true;
          }
        }
      }
      if(update) cnt++;
      else break;
    }
    minus_cycle = (cnt >= N);
  }
};

void solve(long long N, long long M, long long P, std::vector<long long> A, std::vector<long long> B, std::vector<long long> C){
  vvi gt(N);
  rep(i,M){
    A[i]--; B[i]--;
    gt[A[i]].pb(B[i]);
  }
  auto r1 = reachable_from(gt, 0);
  auto r2 = reachable_to(gt, N-1);
  dump(r1,r2);
  int sz = 0;
  vi mp(N);
  rep(i,N){
    if(r1[i] && r2[i]) mp[i] = sz++;
    else mp[i] = -1;
  }
  Graph g(sz);
  rep(i,M){
    ll a = mp[A[i]]; ll b = mp[B[i]];
    if(a<0||b<0) continue;
    g[a].pb(Edge(-(C[i]-P),b));
  }
  if(!r1[0]){
    exit(1);
    return;
  }
  dump(mp);
  dump(g);
  auto bf = BellmanFord(g);
  dump(bf.dist);
  if(bf.minus_cycle) cout << "-1" << endl;
  else cout << max(0LL,-bf.dist[mp[N-1]]) << endl;
}

int main(){
  std::cout << std::fixed << std::setprecision(15);
  long long N;
  scanf("%lld",&N);
  long long M;
  scanf("%lld",&M);
  long long P;
  scanf("%lld",&P);
  std::vector<long long> A(M);
  std::vector<long long> B(M);
  std::vector<long long> C(M);
  for(int i = 0 ; i < M ; i++){
    scanf("%lld",&A[i]);
    scanf("%lld",&B[i]);
    scanf("%lld",&C[i]);
  }
  solve(N, M, P, std::move(A), std::move(B), std::move(C));
  return 0;
}


Measured memory_bytes: 768