#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
using namespace std;

/***** type *****/
using ll = long long;
using ld = long double;
using ml = boost::multiprecision::cpp_int;
using md = boost::multiprecision::cpp_dec_float_100;
template <class T> using vt = vector<T>;
template <class T> using vvt = vector<vector<T>>;
template <class T> using vvvt = vector<vector<vector<T>>>;
template <class T> using uset = unordered_set<T>;
template <class T1, class T2> using umap = unordered_map<T1, T2>;

/***** define *****/
#define all(c) (c).begin(), (c).end()            // begin to end
#define coutld cout << fixed << setprecision(10) // cout long double
#define rep(i, b, e) for (ll i = b; i < e; i++)  // repeat
#define repr(i, b, e) for (ll i = b; e < i; i--) // repeat reverse
#define pair NyaaPair                            // nyaa pair
#define first f                                  // pair::first
#define second s                                 // pair::second
/***** const value *****/
#define llong_max 9223372036854775807            // 9 * 10^18
#define ldbl_max 1.79769e+308                    // 1.7 * 10^308
#define pi 3.1415926535897932                    // 3.14 ...
#define loop_end 9223372036854775806             // LLONG_MAX-1
/***** for each macro *****/
#define fori(i, ...) if(ll i = -1) for(__VA_ARGS__) if(i++, true)
#define each(i, e, c) fori(i, auto& e: c)
#define forir(i, v, ...) if(ll i=(ll)v.size())for(__VA_ARGS__)if(i--,true)
#define eachr(i, e, c) forir(i, auto e = c.rbegin(); e != c.rend(); ++e)

/***** lambda *****/
auto Count = [] // long long count value
(auto b, auto e, auto x) { return (ll)count(b, e, x); };
auto CtoL = [] // char to number
(auto c) { return (ll)(c - '0'); };
auto CeilD = [] // long double ceiling div
(auto a, auto b) { return ceil((ld)a / (ld)b); };
auto Fix = [] // fix value
(auto b, auto e, auto fix)
{ for (auto it = b; it != e; ++it) *it += fix; };
auto LtoC = [] // number to char
(auto n) { return (char)('0' + n); };
auto Pow = [] // long long pow
(auto a, auto b) { return (ll)pow(a, b); };
auto Pow2 = [] // long long pow2
(auto n) { return (1LL << n); };
auto Pow10 = [] // long long pow10
(auto n) { return (ll)pow(10, n); };
auto Size = []  // long long collection size
(auto& c) { return (ll)(c).size(); };
auto Sum = [] // long long accumulate
(auto b, auto e) { return accumulate(b, e, 0LL); };

/***** template *****/
template <class T> void MakeVVT
(ll ys, ll xs, vvt<T>& v, T fill = T())
{	// vector<vector<T>> resize + fill
	v.resize(ys); rep(y, 0, ys) v[y].resize(xs, fill);
}
template <class T> void MakeVVVT
(ll zs, ll ys, ll xs, vvvt<T>& v, T fill = T())
{	// vector<vector<vector<T>>> resize + fill
	v.resize(zs); rep(z, 0, zs) MakeVVT(ys, xs, v[z], fill);
}
template <class T> void InputVT
(ll xs, vt<T>& v, T fix = T())
{	// input vector<T> (T != struct) + fix
	v.resize(xs); rep(i, 0, xs) { cin >> v[i]; v[i] += fix; }
}
template <class T> void InputVVT
(ll ys, ll xs, vvt<T>& v, T fix = T())
{	// input vector<vector<T>> (T != struct) + fix
	MakeVVT(ys, xs, v, fix);
	rep(y, 0, ys) rep(x, 0, xs) { cin >> v[y][x]; v[y][x] += fix; }
}
template <class T> void InputVVVT
(ll zs, ll ys, ll xs, vvvt<T>& v, T fix = T())
{	// input vector<vector<vector<T>>> (T != struct) + fix
	v.resize(zs); rep(z, 0, zs) InputVVT(ys, xs, v[z], fix);
}
template <class T1, class T2> struct NyaaPair
{	// nyaa pair template
	T1 f; T2 s;
};
template <class T1, class T2> bool
operator < (const NyaaPair<T1, T2>& l, const NyaaPair<T1, T2>& r)
{	// nyaa pair template operator <
	return (l.f != r.f) ? l.f < r.f : l.s < r.s;
}
template <class T1, class T2> bool
operator > (const NyaaPair<T1, T2>& l, const NyaaPair<T1, T2>& r)
{	// nyaa pair template operator >
	return (l.f != r.f) ? l.f > r.f : l.s > r.s;
}

/**************************************/
/********** BEGIN OF NYA LIB **********/
/**************************************/

namespace NyaGadget {}

namespace NyaGadget
{
	struct BellmanFordEdge
	{
		long long from = 0;
		long long to = 0;
		long long cost = 0;
	};

	struct GT_BellmanFord
	{
		// 到達不可能なら無視するというフラグ
		vt<bool> ignore;

		bool Run
		(long long s, long long vmax, const vector<BellmanFordEdge>& edge, long long inf, vector<long long>& res)
		{
			res.resize(vmax, LLONG_MAX);
			res[s] = 0;
			for (long long i = 0; i < vmax; i++)
			{
				bool update = false;
				for (auto& e : edge)
				{
					if (ignore[e.to]) continue;
					if (res[e.from] != inf && res[e.from] + e.cost < res[e.to])
					{
						res[e.to] = res[e.from] + e.cost;
						update = true;
					}
				}
				if (!update) break;
				if (i == vmax - 1 && update) return false;
			}

			return true;
		}
	};
}

namespace NyaGadget
{
	/*** DFSライブラリ ***/

	struct NyaaDFS
	{
		//vector<vector<long long>> g;

		/**
		@brief DFS処理関数
		@param r 頂点vの根
		@param v 現在の頂点
		**/
		void Run(long long r, long long v, const vector<vector<long long>>& g, vector<bool>& res)
		{	// 頂点の更新処理
			res[v] = true;
			for (auto e : g[v])
			{	// 後戻りしないようにする
				if (e == r) continue;
				if (res[e]) continue;
				Run(v, e, g, res);
			}
		}
	};
}

/**************************************/
/*********** END OF NYA LIB ***********/
/**************************************/

using namespace NyaGadget;
//using mll = ModLL< 1000000007 >;
//using mll = ModLL< 998244353 >;

int main(void)
{
	ll N, M, P; cin >> N >> M >> P;

	vector<BellmanFordEdge> edge(M);
	each(i, e, edge)
	{
		cin >> e.from >> e.to >> e.cost;
		e.from--, e.to--, e.cost = P - e.cost;
	}

	// 任意の頂点vからゴールN-1への到達不可能性を調べる
	vvt<ll> g(N);
	each(i, e, edge) g[e.from].push_back(e.to);
	GT_BellmanFord bf;
	bf.ignore.resize(N, false);
	NyaaDFS dfs;
	rep(v, 1, N-1)
	{
		vt<bool> res(N, false);
		dfs.Run(-1, v, g, res);
		if (!res[N - 1]) bf.ignore[v] = true;
	}

	vector<long long> res;
	if (!bf.Run(0, N, edge, LLONG_MAX, res))
	{
		cout << -1 << endl;
		return 0;
	}

	if (-res.back() < 0) cout << 0;
	else cout << -res.back();
	return 0;
}


Measured memory_bytes: 512