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

//typedef
//------------------------------------------
typedef long long LL;
typedef vector<LL> VL;
typedef vector<VL> VVL;
typedef vector<string> VS;
typedef pair<LL, LL> PLL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);
const int MOD = 1000000007;

// grid
//--------------------------------------------
VL dx = {0, 1, 0, -1};
VL dy = {1, 0, -1, 0};
VL dx2 = {-1, 0, 1, -1, 1, -1, 0, 1};
VL dy2 = {-1, -1, -1, 0, 0, 1, 1, 1};

//debug
//--------------------------------------------
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

//IO accelerate
//--------------------------------------------
struct InitIO {
    InitIO() {
        cin.tie(nullptr);
        ios_base::sync_with_stdio(false);
        cout << fixed << setprecision(30);
    }
} init_io;

//template
//--------------------------------------------
template<typename T>
istream& operator >>(istream& is, vector<T>& vec) {
  for(T& x: vec) is >> x;
  return is;
}
template<typename T>
ostream& operator <<(ostream& os, const vector<T>& vec) {
  for(int i=0; i<vec.size(); i++){
    os << vec[i] << ( i+1 == vec.size() ? "" : "\t" );
  }
  return os;
}
template<typename T>
ostream& operator <<(ostream& s, const vector<vector<T>>& vv) {
	for (int i = 0; i < vv.size(); ++i) {
		s << vv[i] << endl;
	}
	return s;
}

// 多重vector
// auto dp=make_v<int>(4,h,w) みたいに使える
template<typename T>
vector<T> make_v(size_t a){return vector<T>(a);}

template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
  return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

// 多重vectorのためのfill
// fill_v(dp,0) みたいに使える
template<typename T,typename V>
typename enable_if<is_class<T>::value==0>::type
fill_v(T &t,const V &v){t=v;}

template<typename T,typename V>
typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t,const V &v){
  for(auto &e:t) fill_v(e,v);
}

//main code
template<typename T> class bellman_ford {
public:
    struct edge{
        int from, to;
        T cost;
    };
    int V;
    T inf;
    vector<T> d;
    vector<edge> es; // 辺集合
	vector<vector<int>> ve; // 隣接リスト
	vector<bool> reachable;
    bellman_ford(int node_size) : V(node_size), inf(numeric_limits<T>::max()/2), d(V, inf), ve(V), reachable(V, false) {}
    void add_edge(int from, int to, T cost){
        es.push_back((edge){from, to, cost});
    }
	void add_ve(int from, int to) {
		ve[from].push_back(to);
	}
    //sからの最短路長およびsからたどり着ける負の閉路の検出(trueなら負の閉路が存在する)
    bool solve(int s){
        int cnt = 0;
        d[s] = 0;
        while(cnt < V){
            bool update = false;
            for(auto& e : es){
                if(d[e.from] != inf && d[e.to] > d[e.from] + e.cost){
                    d[e.to] = d[e.from] + e.cost;
                    update = true;
                }
            }
            if(!update) break;
            cnt++;
        }
        return (cnt == V);
    }
	void dfs(int v){
		if(reachable[v]) return;
		reachable[v] = true;
		for (auto&& next : ve[v]) {
			dfs(next);
		}
	}
	// s,t間にある負閉路の検出(solve後に行う)
	// sから辿れる負閉路は検出できてるはずなので，そこからtに行けるか
	bool find_negative_loop_st(int t) {
		for(auto& e : es){
			if(d[e.from] != inf && d[e.to] > d[e.from] + e.cost){
				// e.toからtまで行けるか検証
				dfs(e.to);
				if (reachable[t]) return true;
				fill(ALL(reachable),false);
				dfs(e.from);
				if (reachable[t]) return true;
				fill(ALL(reachable),false);
			}
		}
		return false;
	}
    //すべての負の閉路の検出(trueなら負の閉路が存在する)
    bool find_negative_loop(){
        fill(d.begin(), d.end(), (T)0);
        int cnt = 0;
        while(cnt < V){
            bool update = false;
            for(auto& e : es){
                if(d[e.to] > d[e.from] + e.cost){
                    d[e.to] = d[e.from] + e.cost;
                    update = true;
                }
            }
            if(!update) break;
            cnt++;
        }
        return (cnt == V);
    }
    // s, t 間の最短距離が非有界
    bool shortest_path_infinite(int s, int t){
        d[s] = 0;
        for(int i = 0; i < 2*V-1; i++){
            for(auto& e : es){
                if(d[e.from] != inf && d[e.to] > d[e.from] + e.cost){
                    d[e.to] = d[e.from] + e.cost;
                    if(i >= V-1){
                        if(e.to == t) return true;
                        d[e.to] = -inf;
                    }
                }
            }
        }
        return false;
    }
};

int main(int argc, char const* argv[])
{
	int n,m,p;
	cin >> n >> m >> p;
	bellman_ford<LL> bel(n);
	for (int i = 0; i < m; i++) {
		int a,b,c;
		cin >> a >> b >> c;
		bel.add_edge(--a, --b, -c + p);
		bel.add_ve(a,b);
	}
	if (bel.solve(0)) {
		if(bel.find_negative_loop_st(n-1)) cout << -1 << endl;
		else cout << max(-bel.d[n-1],(LL)0) << endl;
	}
	else {
		cout << max(-bel.d[n-1], (LL)0) << endl;
	}
	return 0;
}


Measured memory_bytes: 640