#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

#define EPS 1e-14
#define PI 3.1415926535897932384626433832795
#define MOD 1000000007
#define INFLL (ll)1e18 //Long long infinity
#define INF (int)1e9 //Int infinity
#define MX 100005

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vd> vvd;
typedef vector<string> vstr;

#define us unordered_set
#define um unordered_map
#define bs bitset

#define RANGE(i,a,b,d) for (int i=min((int)a,(int)b); i<max((int)a,(int)b); i+=d)
#define RRANGE(i,a,b,d) for (int i=max((int)a,(int)b); i>min((int)a,(int)b); i+=d)
#define FOR(i,a,b) RANGE(i,a,b,1)
#define RFOR(i,a,b) RRANGE(i,a,b,-1)
#define REP(i,s) FOR(i,0,s)
#define RREP(i,s) RFOR(i,s-1,-1)
#define FORIT(it,l) for (auto it = l.begin(); it != l.end(); it++)
#define EACH(x,v) for (auto &x : v)

#define sz(x) (int)(x).size()
#define len(x) (int)sizeof(x)/sizeof(*x)
#define mp make_pair
#define pb push_back
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define contains(m,x) (m.find(x) != m.end()) // check if an element in a map
#define isIn(S, s) (S.find(s) != string::npos) // check if substring

#define pv(v) EACH(x, v) cout << x << " "; cout << endl; // print vector/array
#define pvv(vv) EACH(xx, vv){pv(xx);} // print 2-d vector/2-d array
#define pm(m) EACH(x, m) cout << x.F << ":" << x.S << " "; cout << endl; //print map/lookup table

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

namespace std{
  // Used for hashing pair
  template <> struct hash<pi>{
    size_t operator()(const pi&x)const{
      ll P=38923, Q=109797901;
      return (size_t)((x.F*P+x.S)%Q);
    }
  };
};

// This is min queue
template<class T> using pqg = priority_queue<T, vector<T>, greater<T>>;

template <typename T>
void print(T t){
  cout << t << endl;
}

//Python style printing
template<typename T, typename... Args>
void print(T t, Args... args){
  cout << t << " ";
  print(args...);
}

/**
* Description: Shortest Path w/ negative edge weights
    * Can be useful with linear programming
    * Constraints of the form x_i-x_j<k
*/

template<int SZ> struct BellmanFord {
    bool bad[SZ]; // reachable from source and a negative cycle
    vector<pair<pi,int>> edge;
    ll dist[SZ];

    void addEdge(int A, int B, int C) {
      edge.pb({{A,B},C});
    }

    ll query(int x) {
        if (bad[x]) return -INFLL;
        return dist[x];
    }

    void gen(int s) {
        REP(i,SZ) dist[i] = INFLL, bad[i] = 0;
        dist[s] = 0;

        REP(i,SZ) for (auto a: edge) if (dist[a.F.F] < INFLL) 
            dist[a.F.S] = min(dist[a.F.S], dist[a.F.F]+a.S);

        for (auto a: edge) if (dist[a.F.F] < INFLL)
            if (dist[a.F.S] > dist[a.F.F]+a.S) bad[a.F.S] = 1;

        REP(i,SZ) for (auto a: edge)
            if (bad[a.F.F]) bad[a.F.S] = 1;
    }
};

const int N = 2505;
BellmanFord<N> bf;

int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m, p;
  cin >> n >> m >> p;
  REP(i, m) {
    int a, b, c;
    cin >> a >> b >> c;
    a--;
    b--;
    bf.addEdge(a, b, p-c);
  }
  bf.gen(0);
  ll sol = bf.query(n-1);
  if(sol == -INFLL) cout << -1 << "\n";
  else if(sol > 0) cout << 0 << "\n";
  else cout << -sol << "\n";
  return 0;
}


Measured memory_bytes: 480