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

const int MOD1=1000000007;
const int MOD2=998244353;
const long double PI=3.1415926535897932;
const long long MAXLL=9223372036854775807;
const long long INF=2305843009213693951;
const int dx[]={0,1,0,-1,1,-1,1,-1};
const int dy[]={1,0,-1,0,1,1,-1,-1};

#define ll long long
#define ull unsigned long long
#define ld long double
#define pll pair<long long,long long>
#define pcc pair<char,char>
#define vl vector<long long>
#define vvl vector<vector<long long>>
#define vvvl vector<vector<vector<long long>>>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vs vector<string>
#define vb vector<bool>
#define vvb vector<vector<bool>>
#define vp vector<pair<long long,long long>>
#define umap unordered_map
#define uset unordered_set
#define Lqueue priority_queue<long long>
#define Squeue priority_queue<long long,vector<long long>,greater<long long>>
#define fi first
#define se second
#define mp make_pair
#define mt make_tuple
#define eb emplace_back

#define unless(a) if(!(a))
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define rbf(a,x) for(auto& a:x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep2(i,s,n) for(int i=(s);i<(n);i++)
#define bitrep(i,s,n) for(int i=(s);i<(1LL<<(n));i++)
#define bitcheck(bit,i) (bit)&(1LL<<(i))
#define Maxe(x) *max_element((x).begin(),(x).end())
#define Mine(x) *min_element((x).begin(),(x).end())
#define Size(x) ((long long)(x).size())
#define Lin(s) getline(cin,(s))

void Yes(bool a){cout<<(a?"Yes":"No")<<endl;}
void YES(bool a){cout<<(a?"YES":"NO")<<endl;}
template<class T,class U> auto max(T a,U b){return a>b?a:b;}
template<class T,class U> auto min(T a,U b){return a<b?a:b;}
long long gcd(long long a,long long b){return b?gcd(b,a%b):a;}
long long lcm(long long a,long long b){return a/gcd(a,b)*b;}
long long cutup(long long a,long long b){return (a+b-1)/b;}
long long popcnt(long long a){return __builtin_popcountll(a);}
template<class T,class U> inline bool chmin(T& a,U b){if(a>b){a=b;return true;}return false;}
template<class T,class U> inline bool chmax(T& a,U b){if(a<b){a=b;return true;}return false;}
struct edge{long long to,cost;};
struct edge2{long long from,to,cost;};

//BellmanFord
//O(VE)
struct BellmanFord{
    int V;
    vector<long long> d;
    vector<edge2> Es;
    BellmanFord(int v):V(v),d(v){}
    void add(int f,int t,long long c){
        edge2 E;
        E.from=f;
        E.to=t;
        E.cost=c;
        Es.emplace_back(E);
    }

    //-INFの場合、負閉路を用いて無限にコストを下げられる
    //trueを返す場合に負閉路が存在する
    bool build(int s){
        bool c=false;
        for(int i=0;i<V;i++)d[i]=INF;
        d[s]=0;
        for(int i=0;i<V-1;i++){
            for(auto &e:Es){
                if(d[e.from]==INF)continue;
                if(d[e.from]+e.cost<d[e.to])d[e.to]=d[e.from]+e.cost;
            }
        }
        for(int i=0;i<V;i++){
            for(auto &e:Es){
                if(d[e.from]==INF)continue;
                if(d[e.from]+e.cost<d[e.to]){
                    c=true;
                    d[e.to]=-INF;
                }
            }
        }
        return c;
    }
};

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll n,m,p;
    cin>>n>>m>>p;
    BellmanFord B(n);
    rep(i,m){
        ll a,b,c;
        cin>>a>>b>>c;
        a--;b--;
        c=-c;
        c+=p;
        B.add(a,b,c);
    }
    B.build(0);
    ll res=max(-B.d[n-1],0);
    if(res==INF)cout<<-1<<endl;
    else cout<<res<<endl;
}

Measured memory_bytes: 3804