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

# define REP(i,n) for (int i=0;i<(n);++i)
# define rep(i,a,b) for(int i=a;i<(b);++i)
# define p(s) std::cout << s ;
# define pl(s)  std::cout << s << endl;
# define printIf(j,s1,s2) cout << (j ? s1 : s2) << endl;
# define YES(j) cout << (j ? "YES" : "NO") << endl;
# define Yes(j) std::cout << (j ? "Yes" : "No") << endl;
# define yes(j) std::cout << (j ? "yes" : "no") << endl;
# define all(v) v.begin(),v.end()
# define showVector(v) REP(i,v.size()){p(v[i]);p(" ")} pl("")
template<class T> inline bool chmin(T &a, T b){ if(a > b) { a = b; return true;} return false;}
template<class T> inline bool chmax(T &a, T b){ if(a < b) { a = b; return true;} return false;}
typedef long long int ll;
typedef pair<ll,ll> P_ii;
typedef pair<double,double> P_dd;

template<class T>
vector<T> make_vec(size_t a){
    return vector<T>(a);
}

template<class T, class... Ts>
auto make_vec(size_t a, Ts... ts){
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}

template<typename T,typename V>
typename enable_if<is_class<T>::value==0>::type
fill_v(T &t,const V &v){t=v;}

template<typename T,typename V>
typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t,const V &v){
  for(auto &e:t) fill_v(e,v);
}


const int MOD = 1000000007;
const int inf=1e9+7;
const ll longinf=1LL<<60 ;

void addM(long long &a, long long b) {
    a += b;
    if (a >= MOD) a -= MOD;
}

void mulM(long long &a, long long b) {
    a = ((a%MOD)*(b%MOD))%MOD ;
}

const int MAX = 510000;
long long fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

// 二項係数計算
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

vector<ll> divisor(ll n){
    vector<ll> res;
    for(ll i = 1; i * i <= n; i++){
        if(n % i == 0){
            res.push_back(i);
            if(i != n / i) res.push_back(n / i);
        }
    }
    return res;
}

const ll INF = 1LL << 50;
 
ll N, M, P;
const int NMAX = 5050;
const int MMAX = 5050;
int a[MMAX], b[MMAX];
ll c[MMAX];
ll dist[NMAX];

// 負の閉路を検出した場合は特別に対応し、
// 存在しない場合には最短経路を出力する問題

int main(void) {
  cin >> N >> M >> P;
 
  for (int i = 0; i < M; ++i) {
    cin >> a[i] >> b[i] >> c[i];
    c[i] = P - c[i];
  }
  
  for (int i = 0; i < N; ++i) {
    dist[i] = INF;
  }
 
  dist[0] = 0;
  for (int loop = 0; loop < N - 1; ++ loop) {
    for (int i = 0; i < M; ++i) {
 
    if (dist[a[i] - 1] == INF) continue;
 
    if (dist[b[i] - 1] > dist[a[i] - 1] + c[i]) {
        dist[b[i] - 1] = dist[a[i] - 1] + c[i];
      }
    }
  }
 
  ll ans = dist[N - 1];
 
  bool negative[NMAX];
 
  for (int i = 0; i < N; ++i) {
    negative[i] = false;
  }
 
  for (int loop = 0; loop < N ; ++loop) {
    for (int i = 0; i < M; ++i) {
      if (dist[a[i] - 1] == INF) continue;
 
      if (dist[b[i] - 1] > dist[a[i] - 1] + c[i]) {
        dist[b[i] - 1] = dist[a[i] - 1] + c[i];
        negative[b[i] - 1] = true;
      }
 
      if (negative[a[i] - 1] == true) {
        negative[b[i] - 1] = true;
      }
    }
  }
 
  if (negative[N-1])
    cout << -1 << endl;
  else
    cout << max(-ans,0LL) << endl;
 
  return 0;
}

Measured memory_bytes: 384