// Original C++ solution (slower):
#include<bits/stdc++.h>

#include<ext/pb_ds/assoc_container.hpp>

#include<ext/pb_ds/tree_policy.hpp>



using namespace std;

using namespace __gnu_pbds;



/* msi1427 */



#define ll           long long

#define ull          long long unsigned

#define LD           long double

#define FOR(i,n)     for(int i=0;i<n;i++)

#define FLR(i,n)     for(ll i=0;i<n;i++)

#define RFOR(i,n)    for(int i=n-1;i>=0;i--)

#define RFLR(i,n)    for(ll i=n-1;i>=0;i--)

#define rep(i,a,b)   for(int i=a;i<=b;i++)

#define repl(i,a,b)  for(ll i=a;i<=b;i++)

#define casep(z)     cout << "Case " << z << ": ";

#define Fast         ios_base::sync_with_stdio(0);cin.tie(0);

#define sz(a)        a.size()

#define all(x)       x.begin(),x.end()

#define SORT(a,n)    sort(a,a+n)

#define RSORT(a,n)   sort(a,a+n,greater<ll>())

#define pii          pair<int,int>

#define pll          pair<ll,ll>

#define tll          tuple<ll,ll,ll>

#define VSORT(v)     sort(all(v))

#define VRSORT(v)    sort(v.rbegin(),v.rend())

#define pb           push_back

#define eb           emplace_back

#define pf           push_front

#define pob          pop_back()

#define pof          pop_front()

#define ff           first

#define ss           second

#define tt           true

#define fs           false

#define MP           make_pair

#define MEM(x,n)     memset((x),n,sizeof(x))

#define bsrch(a,n,x) binary_search(a,a+n,x)

#define vi           vector<int>

#define vll          vector<ll>

#define PI           acos(-1.0)

#define LB(a,x)      (lower_bound(all(a),x)-a.begin()) //  first element in the range [first,last) which does not compare less than val.

#define UB(a,x)      (upper_bound(all(a),x)-a.begin()) //  first element in the range [first,last) which compares greater than val.

#define PQ           priority_queue

#define heap         PQ< ll , vector<ll> , greater < ll > >

#define REV(x)       reverse(all(x))

#define mpii         map<int,int>

#define mpll         map<ll,ll>

#define cig          cin.ignore()

#define INF          (ll)1e18

#define EPS          1e-9

#define prec(n)      fixed << setprecision(n)

#define lb           lower_bound

#define ub           upper_bound

#define fin          freopen("in.txt","r",stdin)

#define fout         freopen("out.txt","w",stdout)

#define sc           scanf

#define pt           printf

#define np           next_permutation

#define IT(it,x)     for(auto it=x.begin();it!=x.end();it++)

#define sci(x)       scanf("%d",&x);

#define scl(x)       scanf("%lld",&x);

#define scd(x)       scanf("%lf",&x);

#define scs(x)       scanf("%s",x);



#define min3(a,b,c)     min(a,min(b,c))

#define max3(a,b,c)     max(a,max(b,c))

#define min4(a,b,c,d)   min(min(a,b),min(c,d))

#define max4(a,b,c,d)   max(max(a,b),max(c,d))

#define max5(a,b,c,d,e) max(max3(a,b,c),max(d,e))

#define min5(a,b,c,d,e) min(min3(a,b,c),min(d,e))

#define EulerGamma      0.57721566490153286060651209



typedef

tree<

  ll,

  null_type,

  less<ll>,

  rb_tree_tag,

  tree_order_statistics_node_update>

ordered_set;



ll dx[] = {1,-1,0,0};

ll dy[] = {0,0,1,-1};



ll ceiling(ll x,ll y)

{

    if(x%y) return ((x/y)+1);

    else return (x/y);

}



ll gcd(ll x,ll y)

{

    return ((y==0)?x:gcd(y,x%y));

}



ll lcm(ll x,ll y)

{

    return ((x*y)/gcd(x,y));

}



ll BMod(ll B,ll P,ll M)

{

    ll R=1;

    B=B%M;

    while(P)

    {

        if(P&1)

            R=(R*B)%M;

        P >>= 1;

        B=(B*B)%M;

    }

    return R;

}



bool check(ll n,ll pos) {return (n&(1<<pos));}

ll SET(ll n,ll pos){return (n|(1<<pos));}

ll RESET(ll n,ll pos) {return(n&~(1<<pos));}

mt19937 rng32(chrono::steady_clock::now().time_since_epoch().count());



#define MOD 1000000007

#define MAX 6005



ll n,m,p,a[MAX],b[MAX],c[MAX],d[MAX];

bool vf[MAX],vb[MAX];

vector<ll>rad[MAX],ad[MAX];



void dfs_back(ll xx){

    if(vb[xx]) return;

    vb[xx]=true;

    for(auto node : rad[xx]) dfs_back(node);

    return;

}



void dfs_front(ll xx){

    if(vf[xx]) return;

    vf[xx]=true;

    for(auto node : ad[xx]) dfs_front(node);

    return;

}



struct edge{

    ll u,v,w;

}s[MAX];



int main()

{

    Fast

    cin>>n>>m>>p;

    FLR(i,m){

        cin>>a[i]>>b[i]>>c[i];

        rad[b[i]].pb(a[i]);

        ad[a[i]].pb(b[i]);

    }

    dfs_back(n);

    dfs_front(1);

    set<ll>st;

    ll cc = 0;

    FLR(i,m) if(vf[a[i]] && vf[b[i]] && vb[a[i]] && vb[b[i]]) {

        s[cc].u=a[i];

        s[cc].v=b[i];

        s[cc].w=p-c[i];

        cc++;

        st.insert(a[i]);

        st.insert(b[i]);

    }

    FLR(i,MAX) d[i]=INF;

    d[1]=0;

    FLR(i,sz(st)){

        FLR(j,cc){

            if(d[s[j].u]+s[j].w<d[s[j].v]) d[s[j].v] = d[s[j].u]+s[j].w;

        }

    }

    bool flag = false;

    FLR(i,sz(st)){

        FLR(j,cc){

            if(d[s[j].u]+s[j].w<d[s[j].v]) {

                d[s[j].v] = d[s[j].u]+s[j].w;

                flag = true;

            }

        }

    }

    if(flag) cout << -1 << "\n";

    else cout << ((d[n]>0)?0LL:(d[n]*(-1LL))) << "\n";

}

/*



*/


// Optimized solution to the same problem (faster):
// problem: longest distance from 0 to V-1, checking for positive cycle only on this path

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll INF = 1 << 30;



struct Tadj {

	int id, w;

};

vector<vector<Tadj>> adjList;

int V;



vector<ll> ld;



vector<bool> visited;

void dfs(int u) {

   if (visited[u]) return;

   visited[u] = 1;

   for (Tadj v : adjList[u])

      dfs(v.id);

}



/* O(V*E) - retorna true se há um ciclo positivo entre 0 e V-1 */

bool belmman_ford(int s) {

   ld.assign(V, -INF); ld[s] = 0;



   ll first0, first1;

   for (int i = 0; i < V; i++) {

      // para cada aresta u --v.w--> v.id

      for (int u = 0; u < V; u++)

         for (Tadj v : adjList[u]) {

            if (ld[u] + v.w > ld[v.id] && ld[u] > -INF) {

               ld[v.id] = ld[u] + v.w;



               // se ainda conseguiu relaxar depois das V-1 vezes anteriores

               if (i == V-1) {

                  visited.assign(V, 0);

                  dfs(v.id);

                  if (visited[0] || visited[V-1]) return true;

               }

            }

         }

   }



   return false;

}



int main() {

   int E, P; cin >> V >> E >> P;

   adjList.assign(V, vector<Tadj>());

   while (E--) {

      int u, v, w; cin >> u >> v >> w; u--; v--; w -= P;

      adjList[u].push_back({v, w});

   }



   cout << (belmman_ford(0)? -1 : max(ld[V-1], 0ll)) << endl;

}

// Fastest known solution for this problem: