#ifndef ONLINE_JUDGE
#define _GLIBCXX_DEBUG
#endif

#define _USE_MATH_DEFINES
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
//https://boostjp.github.io/tips/multiprec-int.html
using lll = __int128_t;

#define YES cout<<"Yes\n"
#define NO cout<<"No\n"
#define YN {cout<<"Yes\n";}else{cout<<"No\n";}// if(a==b)YN;
#define NO2 cout<<"-1\n"

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i, n) for (int i=int(n)-1; i>=0; --i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    using P=pair<ll,ll>;
    int N,M,K;
    cin >> N >> M >> K;
    ll INF = ll(1e18);
    vector<vector<ll>> dist(N, vector<ll>(M,INF));
    vector<vector<P>> G(N);
    rep(i,M) {
        ll u,v,t;
        cin>>u>>v>>t;
        G[u].emplace_back(P{v,t});
        G[v].emplace_back(P{u,t});
    }

    queue<P> que;
    que.push(P{0,0});
    dist[0][0] = 0;
    while(que.size()) {
        auto [cur, time] = que.front();
        que.pop();
        for (auto [nxt, cost]: G[cur]) {
            if (time+cost < dist[nxt][time+cost%M]) {
                dist[nxt][time+cost%M] = time+cost;
                que.push(P{nxt, time+cost});
            }
        }
    }
    ll ans = INF;
    rep(i,M) ans = min(ans, dist[N][i]);
    cout << ans << endl;

}