#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using pii = pair<int, int>;
template <class T>
using V = vector<T>;
template <class T>
using VV = V<V<T>>;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i, n) rep2(i, 0, n)
#define rep2(i, m, n) for (int i = m; i < (n); i++)
#define per(i, b) per2(i, 0, b)
#define per2(i, a, b) for (int i = int(b) - 1; i >= int(a); i--)
#define ALL(c) (c).begin(), (c).end()
#define SZ(x) ((int)(x).size())

constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); }

template <class T, class U>
void chmin(T& t, const U& u) {
    if (t > u) t = u;
}
template <class T, class U>
void chmax(T& t, const U& u) {
    if (t < u) t = u;
}

template <class T, class U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << "," << p.second << ")";
    return os;
}

template <class T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "{";
    rep(i, v.size()) {
        if (i) os << ",";
        os << v[i];
    }
    os << "}";
    return os;
}

#ifdef LOCAL
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << H;
    debug_out(T...);
}
#define debug(...) \
    cerr << __LINE__ << " [" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif

const ll INF = TEN(15);

VV<pii> g;

int main() {
    int T, N, M;
    cin >> T >> N >> M;
    g.resize(N);

    if (T == 0) {
        ll ans = INF;
        V<pair<pii, int>> es;
        rep(i, M) {
            int a, b, w;
            cin >> a >> b >> w;
            --a, --b;
            es.eb(mp(a, b), w);
        }
        rep(i, M) {
            pii pr = es[i].fi;
            int ct = es[i].se;
            int s = pr.fi;
            g.clear();
            g = VV<pii>(N);
            rep(j, M) if (j != i) {
                g[es[j].fi.fi].eb(es[j].fi.se, es[j].se);
                g[es[j].fi.se].eb(es[j].fi.fi, es[j].se);
            }

            V<ll> d(N, INF);
            d[s] = 0;
            using Data = pair<ll, int>;
            priority_queue<Data, V<Data>, greater<Data>> que;
            que.emplace(0ll, s);
            while (!que.empty()) {
                auto t = que.top();
                que.pop();
                int v = t.se;
                if (d[v] < t.fi) continue;
                for (auto& [to, w] : g[v]) {
                    if (d[to] > d[v] + w) {
                        d[to] = d[v] + w;
                        que.emplace(d[to], to);
                    }
                }
            }
            if (d[pr.se] != INF) {
                // debug(pr, d[pr.se], ct);
                chmin(ans, d[pr.se] + ct);
            }
        }
        if (ans == INF) ans = -1;
        cout << ans << endl;
    } else {
        rep(i, M) {
            int a, b, w;
            cin >> a >> b >> w;
            --a, --b;
            g[a].eb(b, w);
        }

        ll ans = INF;

        rep(s, N) {
            V<ll> d(N, INF);
            d[s] = 0;
            using Data = pair<ll, int>;
            priority_queue<Data, V<Data>, greater<Data>> que;
            que.emplace(0ll, s);
            while (!que.empty()) {
                auto t = que.top();
                que.pop();
                int v = t.se;
                if (d[v] < t.fi) continue;
                for (auto& [to, w] : g[v]) {
                    if (d[to] > d[v] + w) {
                        d[to] = d[v] + w;
                        que.emplace(d[to], to);
                    }
                }
            }

            rep(t, N) {
                for (auto& [to, w] : g[t]) {
                    if (to == s) {
                        chmin(ans, d[t] + w);
                    }
                }
            }
        }
        if (ans == INF) ans = -1;
        cout << ans << endl;
    }
    return 0;
}