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

#define REP(i,m,n) for(int i=(m); i<(int)(n); i++)
#define RREP(i,m,n) for(int i=(int)(n-1); i>=m; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define aut(r,v) __typeof(v) r = (v)
#define each(it,o) for(aut(it,(o).begin()); it!=(o).end(); ++it)
#define reach(it,o) for(aut(it,(o).rbegin()); it!=(o).rend(); ++it)
#define fi first
#define se second
#define debug(...) {cerr<<"[L"<<__LINE__<<"] "; _debug(__VA_ARGS__);}

template<typename T1, typename T2> ostream& operator<<(ostream& o, const pair<T1, T2>& p)
{return o<<"("<<p.first<<", "<<p.second<<")";}
template<typename T>string join(const vector<T>&v, string del=", ")
{stringstream s;rep(i,v.size())s<<del<<v[i];return s.str().substr(del.size());}
template<typename T>ostream& operator<<(ostream& o, const vector<T>&v)
{if(v.size())o<<"["<<join(v)<<"]";return o;}
template<typename T>ostream& operator<<(ostream& o, const vector<vector<T> >&vv)
{int l=vv.size();if(l){o<<endl;rep(i,l){o<<(i==0?"[ ":",\n  ")<<vv[i]<<(i==l-1?" ]":"");}}return o;}
template<typename T>ostream& operator<<(ostream& o, const set<T>& st)
{vector<T> v(st.begin(),st.end());o<<"{ "<<join(v)<<" }";return o;}
template<typename T1, typename T2>ostream& operator<<(ostream& o, const map<T1, T2>& m)
{each(p,m){o<<(p==m.begin()?"{ ":",\n  ")<<*p<<(p==--m.end()?" }":"");}return o;}
inline void _debug(){cerr<<endl;}
template<class First, class... Rest>
void _debug(const First& first, const Rest&... rest){cerr<<first<<" ";_debug(rest...);}

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;

const double PI = (1*acos(0.0));
const double EPS = 1e-9;
const ll INF = 0x3f3f3f3f;
const ll INFL = 0x3f3f3f3f3f3f3f3fLL;
const ll mod = 1e9 + 7;

inline void finput(string filename) {
    freopen(filename.c_str(), "r", stdin);
}

struct Edge{
    ll from, to, cost;
    Edge(int from, int to, int cost): from(from), to(to), cost(cost){}
};

ll n,m,p;
vector<Edge> es, es2;
vi g[3000], rg[3000];
bool d[3000], rd[3000];

void dfs(int v, vi* g, bool *d){
    d[v] = true;
    for(auto u : g[v]){
        if(!d[u]) dfs(u, g, d);
    }
}

ll search(int s, int g){
    vl d(n, INFL);
    d[s] = 0;
    rep(i,n){
        rep(j,es2.size()){
            Edge e = es2[j];
            if(d[e.to] > d[e.from] + e.cost){
                d[e.to] = d[e.from] + e.cost;
                if(i == n-1) return -1;
            }
        }
    }
    return max(0ll, -d[g]);
}

int main(){
    ios_base::sync_with_stdio(0);
    // finput("./E/in/a03");

    cin >> n >> m >> p;
    rep(i,m){
        int a,b,c;
        cin >> a >> b >> c;
        a--; b--;
        es.emplace_back(a, b, p-c);
        g[a].push_back(b);
        rg[b].push_back(a);
    }

    fill(d, d+n, false);
    fill(rd, rd+n, false);
    dfs(0, g, d);
    dfs(n-1, rg, rd);
    for(auto e : es){
        if(!d[e.to] || !rd[e.to]) continue;
        if(!d[e.from] || !rd[e.from]) continue;
        es2.push_back(e);
    }

    cout << search(0, n-1) << endl;
    return 0;
}

Measured memory_bytes: 4192