#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
//#pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#endif

#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<time.h>
#include<random>
#include<array>


using namespace std;

#define REP(i, n) for(int i = 0;i < n;++i)
#define REPR(i, n) for(int i = n-1;i >= 0;--i)
#define FOR(i, m, n) for(int i = m;i < n;++i)
#define FORR(i, m, n) for(int i = m-1;i >= n;--i)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v,n) reverse(v,v+n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout<<(x)<<'\n'
#define pe(x) cout<<(x)<<" "
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define lb(v,n) lower_bound(v.begin(), v.end(), (n))
#define ub(v,n) upper_bound(v.begin(), v.end(), (n))
#define int long long
//#define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v) REP(i,v.size())cout << v[i] << ((i == v.size() - 1) ? "\n" : " ")
template<typename T1, typename T2> inline void chmin(T1 & a, T2 b) { if (a > b) a = b; }
template<typename T1, typename T2> inline void chmax(T1& a, T2 b) { if (a < b) a = b; }
typedef pair<int, int>pii;
typedef array<int, 3> arr3;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7; constexpr int MAX = 2000020;
const double pi = acos(-1); constexpr double EPS = 1e-8;
constexpr ll INF = 1e18;
void yes(bool c) { if (c)print("Yes"); else print("No"); };

const int mod = 1000000007;
//const int mod = 998244353;
struct mint {
	ll x; // typedef long long ll;
	mint(ll x = 0) :x((x%mod + mod) % mod) {}
	mint operator-() const { return mint(-x); }
	mint& operator+=(const mint a) {
		if ((x += a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator-=(const mint a) {
		if ((x += mod - a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this; }
	mint operator+(const mint a) const { return mint(*this) += a; }
	mint operator-(const mint a) const { return mint(*this) -= a; }
	mint operator*(const mint a) const { return mint(*this) *= a; }
	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime mod
	mint inv() const { return pow(mod - 2); }
	mint& operator/=(const mint a) { return *this *= a.inv(); }
	mint operator/(const mint a) const { return mint(*this) /= a; }
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }

int P;
struct edge {
	int to, cost;
};
vector<edge>G[100010];
vector<int>Grev[100010];
int val[100010];
int las[100010];
int C[100010];
bool act[100010];
int N;
bool canreach[100010];
bool vis[100010];
void ser(int n) {
	vis[n] = true;
	canreach[n] = true;
	for (auto nxt : Grev[n]) {
		if (vis[nxt])continue;
		ser(nxt);
	}
}
void dfs(int n, int t,int res) {
	las[n] = t;
	val[n] = max(val[n], res);
	act[n] = true;
	for (auto e : G[n]) {
		int nxt = e.to;
		if (!canreach[nxt])continue;
		if (act[nxt]) {
			if (val[nxt]<res+e.cost-P) {
				print(-1); exit(0);
			}
		}
		else {
			if(res+e.cost-P>val[nxt])dfs(nxt, t + 1, res + e.cost-P);
		}
	}
	act[n] = false;
}
void solve() {
	int M; cin >> N >> M >> P;
	REP(i, M) {
		int u, v, c; cin >> u >> v >> c;
		u--, v--;
		G[u].push_back({ v,c });
		Grev[v].push_back(u);
	}
	ser(N - 1);
	//REP(i, N)ser(i);
	REP(i, N)val[i] = -1e18;
	val[0] = 0;
	dfs(0, 0, 0);
	print(max(0LL,val[N - 1]));
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	//int q; cin >> q;
	//while (q--)
	solve();
}




Measured memory_bytes: 6016