#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <iostream>
#include <istream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include <tuple>
#include <iomanip>
#include <climits>
#include <fstream>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
//typedef pair<ll, ll> P;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define revrep(i, n) for(int i = (n)-1; i >= 0; i--)
#define pb push_back
#define f first
#define s second
#define chmin(x, y) x = min(x, y);
#define chmax(x, y) x = max(x, y);

//const ll INFL = LLONG_MAX;//10^18 = 2^60
const ll INFL = 1LL<<60;
//const int INF = INT_MAX;
const int INF = 1 << 30;//10^9
//ll MOD = 1000000007;
ll MOD = 998244353;
double EPS = 1e-11;

vector<ll> dy = {0, 1, 0, -1, 1, 1, -1, -1, 0};
vector<ll> dx = {1, 0, -1, 0, 1, -1, 1, -1, 0};

void pres(double A){printf("%.12lf\n", A);}
void BinarySay(ll x, ll y = 60){rep(i, y) cout << (x>>(y-1-i) & 1); cout << endl;}
ll cnt_bit(ll x){return __builtin_popcountll(x);}

ll pow_long(ll x, ll k){
  ll res = 1;
  while(k > 0){
    if(k % 2) res *= x;
    x *= x; k /= 2;
  }
  return res;
}

ll pow_mod(ll x, ll k){
  x %= MOD;
  ll res = 1;
  while(k > 0){
    if(k % 2){
      res *= x; res %= MOD;
    }
    x *= x; x %= MOD;
    k /= 2;
  }
  return res;
}

ll inverse(ll x){return pow_mod(x, MOD - 2);};

ll gcd(ll a, ll b){
    if(b == 0) return a;
    return gcd(b, a % b);
}

ll lcm(ll x, ll y){
  ll res = x / gcd(x, y);
  res *= y;
  return res;
};


//コンビネーション
const int MAXcomb = 2000010;
ll fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
//facはn!,finvは1/n!
//invは逆元
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAXcomb; 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;
    }
}
ll comb(int n, int k){
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[k] % MOD * finv[n-k] % MOD;
}

const int MAXkai = 200010;
ll kai_memo[MAXkai];
ll kai(ll N){
  if(kai_memo[N] != 0) return kai_memo[N];
  if(N <= 1) return 1;
  return kai_memo[N] = N * kai(N-1) % MOD;
}

ll disit(ll s, ll base = 10){
  ll res = 0;
  while(s){
    res++;
    s /= base;
  }
  return res;
}

//素因数分解O(√n)
vector<pair<ll, ll>> MakePrimeList(ll x) {
    vector<pair<ll, ll>> res;
    for(ll k=2; k*k<=x; k++) {
        if(x % k == 0) {
            ll cnt = 0;
            while(x % k == 0){
              x /= k;
              cnt++;
            }
            res.pb({k, cnt});
        }
    }
    if(x > 1) res.push_back({x, 1});
    return res;
}

ll N, M, P;
struct edge{ll to, cost = 1;};
vector<edge> E[3010], rE[3010];

bool can[3010], rcan[3010];
bool use[3010];
ll dist[3010];

void dfs(ll now){
  can[now] = 1;
  for(edge e: E[now])if(!can[e.to]){
    dfs(e.to);
  }
}

void rdfs(ll now){
  rcan[now] = 1;
  for(edge e: rE[now])if(!rcan[e.to]){
    rdfs(e.to);
  }
}

ll Bellmanford(){
  dfs(0);
  rdfs(N-1);
  rep(i, N)if(can[i]&&rcan[i]) use[i] = 1;
  rep(i, N) dist[i] = INFL;
  dist[0] = 0;
  bool update;
  rep(_, N+2){
    update = 0;
    rep(now, N)if(use[now])for(edge e: E[now])if(use[e.to]){
      if(dist[e.to] > dist[now] + e.cost){
        dist[e.to] = dist[now] + e.cost;
        update = 1;
      }
    }
  }
  if(update) return -INFL;
  return dist[N-1];
}

void solve(){
  cin >> N >> M >> P;
  rep(i, M){
    ll a, b, c;
    cin >> a >> b >> c;
    a--, b--;
    E[a].pb({b, P-c});
    rE[b].pb({a, P-c});
  }
  ll ans = Bellmanford();
  if(ans == -INFL) ans = -1;
  else ans = max(0LL, -ans);
  cout << ans << endl;
}


int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
}


Measured memory_bytes: 768