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

#define NDEBUG
#include <cassert>


typedef long long ll;
typedef long double Double;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<llll> vllll;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<long double> vD;

#define sz(a)  int((a).size())
#define pb  push_back
#define eb  emplace_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define repC3(vari,varj,vark,n)  for(int vari=0;vari<(n)-2;++vari)for(int varj=vari+1;varj<(n)-1;++varj)for(int vark=varj+1;vark<(n);++vark)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))
#define cons make_pair
#define clamp(v,lo,hi) min(max(v,lo),hi)

template <typename T>
inline bool found(set<T> &s, T elem) { return s.find(elem) != s.end(); }
template <typename T>
inline bool found(unordered_set<T> &s, T elem) { return s.find(elem) != s.end(); }
template <typename T, typename U>
inline bool found(map<T,U> &s, U elem) { return s.find(elem) != s.end(); }
template <typename T, typename U>
inline bool found(unordered_map<T,U> &s, U elem) { return s.find(elem) != s.end(); }
template <typename T>
inline bool found(vector<T> &s, T elem) { return find(s.begin(), s.end(), elem) != s.end(); }
inline int found(string &s, string t) { return (int)s.find(t); }
inline int found(string &s, int c) { return (int)s.find(c); }

template<typename T1, typename T2> inline void amin(T1 & a, T2 const & b) { if (a>b) a=b; }
template<typename T1, typename T2> inline void amax(T1 & a, T2 const & b) { if (a<b) a=b; }
template<typename X, typename T> auto vectors(X x, T a) { return vector<T>(x, a); }
template<typename X, typename Y, typename Z, typename... Zs> auto vectors(X x, Y y, Z z, Zs... zs) { auto cont = vectors(y, z, zs...); return vector<decltype(cont)>(x, cont); }

inline ll square(ll x) { return x * x; }
inline ll gcd(ll a, ll b) { while(a) swap(a, b%=a); return b; }
template <typename T>
inline T mod(T a, T b) { return ((a % b) + b) % b; }


struct Edge {
    int from, to, cost;
};

template <typename T>
class BellmanFord {
 public:
    int N;
    vector<T> distance;
    vector<Edge> edges;
    T INF;

 public:
    BellmanFord(int n, T inf) : N(n), distance(n,inf), INF(inf) {}

    void add_edge(int from, int to, int cost) {
        edges.push_back((Edge){from, to, cost});
    }

    bool shortest_path(int s, int g) {
        distance.assign(N, INF);
        distance[s] = 0;

        T minimum_possible = -INF;
        bool updated = true;
        for (int count=0; count<N; ++count) {
            updated = false;
            for (Edge& e: edges) {
                if (distance[e.from] != INF
                    && distance[e.to] > distance[e.from] + e.cost) {
                    distance[e.to] = distance[e.from] + e.cost;
                    updated = true;
                    if (count == N-1) {
                        distance[e.to] = minimum_possible;
                    }
                }
            }
            if (!updated) break;
        }

        for (int count=0; count<N; ++count) {
            for (Edge& e: edges) {
                if (distance[e.from] == minimum_possible && distance[e.to] != minimum_possible) {
                    distance[e.to] = minimum_possible;
                }
            }
        }

        if (distance[g] == minimum_possible) return true;
        return false;
    }
};

ll solve(int N, int M, int P, vi& a, vi& b, vi& c) {

    BellmanFord<ll> bf(N+2, 1e15);
    bf.add_edge(0, 1, 0);
    rep(i,M){
        int from=a[i]+1, to=b[i]+1, cost=c[i];
        bf.add_edge(from, to, P-cost);
    }
    bf.add_edge(N, N+1, 0);

    ll ans = (bf.shortest_path(0, N+1)) ? -1 : max(0LL, -bf.distance[N+1]);

    return ans;
}

int main() {
    int N,M,P; scanf("%d %d %d%*c", &N,&M,&P);
    vi a(M),b(M),c(M);
    rep(i,M) {
        scanf("%d %d %d%*c", &a[i],&b[i],&c[i]);
        a[i]--; b[i]--;
    }
    cout << solve(N,M,P,a,b,c) << endl;
    return 0;
}


Measured memory_bytes: 592