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



typedef unsigned long ul;
typedef unsigned long long ull;
typedef long long ll;
typedef vector<ll> vint;
typedef vector< vector<ll> > vvint;
typedef vector< vector< vector<ll> > > vvvint;
typedef vector<string> vstring;
typedef vector< vector<string> > vvstring;
typedef vector<char> vchar;
typedef vector< vector<char> > vvchar;
typedef vector<long double> vdouble;
typedef vector< vector<long double> > vvdouble;
typedef vector< vector< vector<long double> > > vvvdouble;
typedef pair<ll,ll> pint;
typedef vector<pint> vpint;
typedef vector<bool> vbool;

#define rep(i,n) for(ll i=0;i<n;i++)
#define repf(i,f,n) for(ll i=f;i<n;i++)
#define repr(i,n) for(ll i=n-1;i>=0;i--)
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define ALL(obj) (obj).begin(), (obj).end()
// #define LLONG_MAX 9223372036854775806
#define vmax(vec) *max_element(vec.begin(), vec.end())
#define vmin(vec) *min_element(vec.begin(), vec.end())
#define vsort(vec) sort(vec.begin(), vec.end())
#define vsortgr(vec) sort(vec.begin(), vec.end(), greater<ll>())
#define MOD 1000000007
// #define MOD 998244353
// #define MOD LLONG_MAX
const double PI=3.14159265358979323846;

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; }




int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0,};



void printv(vint &v){
  for(auto e:v) cout<<e<<" ";
  cout<<endl;
}


// 繰り返し二乗法
ll power(ll a, ll b){
  if(a==1)return a;
  // if(a==0)re
  ll res=1;
  while(b>0){
    if(b&1) res=res*a%MOD;
    a=a*a%MOD;
    b>>=1;
  }
  return res;
}

const int MAX=2100000;
 
ll fact[MAX], fact_inv[MAX];
 
void init_fact(ll n){
  fact[0]=1;
  // 階乗の計算
  rep(i, n) fact[i+1]=fact[i]*(i+1)%MOD;
  fact_inv[n]=power(fact[n], MOD-2);
  // 逆元の計算
  for(ll i=n-1;i>=0;i--) fact_inv[i]=fact_inv[i+1]*(i+1)%MOD;
}
 
ll comb(ll n, ll r){
  return (fact[n]*fact_inv[r])%MOD*fact_inv[n-r]%MOD;
}
 
ll perm(ll n, ll r){
  return (fact[n]*fact_inv[n-r])%MOD;
}






int main() {
  // cout<<fixed<<setprecision(10);

  ll n,m,p; cin>>n>>m>>p;

  vector<vpint> edges(n), edges_back(n);
  vector<tuple<ll,ll,ll>> egs;
  rep(i,m){
    ll a,b,c; cin>>a>>b>>c;
    a--; b--;
    edges[a].push_back(mp(b, p-c));
    edges_back[b].push_back(mp(a, p-c));
    egs.emplace_back(a,b,p-c);
  }

  set<ll> A,B,C;
  queue<ll> q;
  q.push(0);
  while(!q.empty()){
    ll from;
    from = q.front(); q.pop();
    if(A.count(from)) continue;
    A.insert(from);

    for(auto tmp:edges[from]){
      ll to, c;
      tie(to, c) = tmp;
      if(A.count(to)) continue;
      q.push(to);
    }
  }

  q.push(n-1);
  while(!q.empty()){
    ll from;
    from = q.front(); q.pop();
    if(B.count(from)) continue;
    B.insert(from);

    for(auto tmp:edges_back[from]){
      ll to, c;
      tie(to, c) = tmp;
      if(B.count(to)) continue;
      q.push(to);
    }
  }

  for(auto e:A){
    if(B.count(e)) C.insert(e);
  }


  vint dist(n, LLONG_MAX);
  dist[0] = 0;

  rep(i, n-1){
    for(auto e:egs){
      ll from, to, c;
      tie(from, to, c) = e;
      if(C.count(from) == 0) continue;
      if(dist[from] == LLONG_MAX) continue;
      chmin(dist[to], dist[from] + c);
    }
  }

  for(auto e:egs){
    ll from, to, c;
    tie(from, to, c) = e;
    if(C.count(from) == 0) continue;
    if(dist[from] == LLONG_MAX) continue;
    if(dist[from] + c < dist[to]){
      puts("-1");
      return 0;
    }
  }


  cout<<-min(dist[n-1], 0ll)<<endl;




}






Measured memory_bytes: 1152