#include <iostream>
using namespace std;
const int INF = 0x3f3f3f3f;
const int MAXN = 1010;
int n, m, x, ct;
int g[MAXN][MAXN];
int gr[MAXN][MAXN];
int dist[MAXN];
int vis[MAXN];
struct node {
    int id;
    int fi;
    int gi;
    friend bool operator<(node a,node b){
        if(a.gi==b.gi)
            return a.fi>b.fi;
        return a.gi>b.gi;
    }
}s[2000000];
int init(){
    memset(dist, 0x3f, sizeof dist);
    memset(vis  , 1 ,sizeof vis);
    dist[n-1]=0;
    for(int i=0;i<n;i++)
    {
        int k=n;
        for(int j=0;j<n;j++)
            if(vis[j]&&dist[j]<dist[k])
                k=j;
        if(k==n)
            break;
        vis[k]=0;
        for(int j=0;j<n;j++)
            if(vis[j]&&dist[k]+gr[k][j]<dist[j])
                dist[j]=dist[k]+gr[k][j];
    }
    return 1;
}
int solve(){
    if(dist[0]==INF)
        return -1;
    ct=0;
    s[ct].id=0;
    s[ct].fi=0;
    s[ct++].gi=dist[0];
    int cnt=0;
    while(ct){
        int id=s[0].id;
        int fi=s[0].fi;
        if(id==n-1)
            cnt++;
        if(cnt==x)
            return fi;
        pop_heap(s,s+ct);
        ct--;
        for(int j=0;j<n;j++)
        {
            if(g[id][j]<INF){
                  s[ct].id=j;
                s[ct].fi=fi+g[id][j];
                ct++;
                push_heap(s,s+ct);
            }
        }
    }
    return -1;
}
int main() {
    while (cin >> n >> m >> x) {
        memset(g, 0x3f, sizeof(g));
        memset(gr, 0x3f, sizeof(gr));
        for (int i = 0; i < n; i++) {
            int p, q, r;
            cin >> p >> q >> r;
            p--;
            q--;
            g[p][q] = g[p][q] <= r ? g[p][q] : r;
            gr[q][p] = gr[q][p] <= r ? gr[q][p] : r;
        }
        init();
        cout << solve() << endl;
    }
    return 0;
}