#include <bits/stdc++.h>
typedef long long ll;
#define pb push_back
using namespace std;


ll n,m,p;
vector<ll> g[100005];
ll vis[2560];
bool ok;
void rech(ll s)
{
        if(ok) return;
        vis[s]=1;
        if(s==n-1) {
                ok=true; return;
        }
        for(auto &j : g[s]) {
                if(vis[j]==0) rech(j);
                if(ok) return;
        }
}
// a structure to represent a weighted edge in graph
struct Edge {
    int src, dest, weight;
};

// a structure to represent a connected, directed and
// weighted graph
struct Graph {
    // V-> Number of vertices, E-> Number of edges
    int V, E;

    // graph is represented as an array of edges.
    struct Edge* edge;
};

// Creates a graph with V vertices and E edges
ll A;
struct Graph* createGraph(int V, int E)
{
    struct Graph* graph = new Graph;
    graph->V = V;
    graph->E = E;
    graph->edge = new Edge[graph->E];
    return graph;
}

// The main function that finds shortest distances
// from src to all other vertices using Bellman-
// Ford algorithm.  The function also detects
// negative weight cycle
bool isNegCycleBellmanFord(struct Graph* graph,
                           int src)
{
    int V = graph->V;
    int E = graph->E;
    int dist[V];

    // Step 1: Initialize distances from src
    // to all other vertices as INFINITE
    for (int i = 0; i < V; i++)
        dist[i] = INT_MAX;
    dist[src] = 0;

    // Step 2: Relax all edges |V| - 1 times.
    // A simple shortest path from src to any
    // other vertex can have at-most |V| - 1
    // edges
    for (int i = 1; i <= V - 1; i++) {
        for (int j = 0; j < E; j++) {
            int u = graph->edge[j].src;
            int v = graph->edge[j].dest;
            int weight = graph->edge[j].weight;
            if (dist[u] != INT_MAX && dist[u] + weight < dist[v])
                dist[v] = dist[u] + weight;
        }
    }

    // Step 3: check for negative-weight cycles.
    // The above step guarantees shortest distances
    // if graph doesn't contain negative weight cycle.
    // If we get a shorter path, then there
    // is a cycle.
    A = dist[n-1];
    for (int i = 0; i < E; i++) {
        int u = graph->edge[i].src;
        int v = graph->edge[i].dest;
        int weight = graph->edge[i].weight;
        if (dist[u] != INT_MAX && dist[u] + weight < dist[v])
            {
                    ok=false;
                    for(ll i=0;i<n;i++) vis[i]=0;
                    rech(v);
                    if(ok) return true;
            }
    }

    return false;
}

// Driver program to test above functions
int main()
{
    /* Let us create the graph given in above example */
    /*int V = 5; // Number of vertices in graph
    int E = 8; // Number of edges in graph
    struct Graph* graph = createGraph(V, E);

    // add edge 0-1 (or A-B in above figure)
    graph->edge[0].src = 0;
    graph->edge[0].dest = 1;
    graph->edge[0].weight = -1;

    // add edge 0-2 (or A-C in above figure)
    graph->edge[1].src = 0;
    graph->edge[1].dest = 2;
    graph->edge[1].weight = 4;

    // add edge 1-2 (or B-C in above figure)
    graph->edge[2].src = 1;
    graph->edge[2].dest = 2;
    graph->edge[2].weight = 3;

    // add edge 1-3 (or B-D in above figure)
    graph->edge[3].src = 1;
    graph->edge[3].dest = 3;
    graph->edge[3].weight = 2;

    // add edge 1-4 (or A-E in above figure)
    graph->edge[4].src = 1;
    graph->edge[4].dest = 4;
    graph->edge[4].weight = 2;

    // add edge 3-2 (or D-C in above figure)
    graph->edge[5].src = 3;
    graph->edge[5].dest = 2;
    graph->edge[5].weight = 5;

    // add edge 3-1 (or D-B in above figure)
    graph->edge[6].src = 3;
    graph->edge[6].dest = 1;
    graph->edge[6].weight = 1;

    // add edge 4-3 (or E-D in above figure)
    graph->edge[7].src = 4;
    graph->edge[7].dest = 3;
    graph->edge[7].weight = -3;

    if (isNegCycleBellmanFord(graph, 0))
        cout << "Yes";
    else
        cout << "No";
        */
    cin >> n >> m >> p;
        struct Graph* graph = createGraph(n, m);
        for(ll i=0;i<m;i++) {
                ll a,b,c;
                cin >> a >> b >> c;
                g[a-1].pb(b-1);
                graph->edge[i].src=a-1;
                graph->edge[i].dest=b-1;
                graph->edge[i].weight=p-c;
        }
        if(isNegCycleBellmanFord(graph, 0)){
                cout << "-1\n";
                //cout << A << endl; return 0;
        }else {
                cout << max(-A, 0LL) << endl; return 0;
        }

    return 0;
}


Measured memory_bytes: 2816