#include <bits/stdc++.h>
using namespace std;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T, typename V>
void ndarray(vector<T>& vec, const V& val, int len) { vec.assign(len, val); }
template <typename T, typename V, typename... Args> void ndarray(vector<T>& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); }
template <typename T> bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template <typename T> bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template <typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
template <typename T> vector<T> sort_unique(vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <typename T> istream &operator>>(istream &is, vector<T> &vec) { for (auto &v : vec) is >> v; return is; }
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T, size_t sz> ostream &operator<<(ostream &os, const array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; }
#if __cplusplus >= 201703L
template <typename... T> istream &operator>>(istream &is, tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <typename... T> ostream &operator<<(ostream &os, const tuple<T...> &tpl) { std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os; }
#endif
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T, typename TH> ostream &operator<<(ostream &os, const unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa) { os << '(' << pa.first << ',' << pa.second << ')'; return os; }
template <typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <typename TK, typename TV, typename TH> ostream &operator<<(ostream &os, const unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m";
#define dbg(x) cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << endl
#else
#define dbg(x) {}
#endif

template <typename T> struct ShortestPath {
    int V, E;
    int INVALID = -1;
    std::vector<std::vector<std::pair<int, T>>> to;
    ShortestPath() = default;
    ShortestPath(int V) : V(V), E(0), to(V) {}
    void add_edge(int s, int t, T len) {
        assert(0 <= s and s < V);
        assert(0 <= t and t < V);
        to[s].emplace_back(t, len);
        E++;
    }

    std::vector<T> dist;
    std::vector<int> prev;
    // Dijkstra algorithm
    // Complexity: O(E log E)
    void Dijkstra(int s) {
        assert(0 <= s and s < V);
        dist.assign(V, std::numeric_limits<T>::max());
        dist[s] = 0;
        prev.assign(V, INVALID);
        using P = std::pair<T, int>;
        std::priority_queue<P, std::vector<P>, std::greater<P>> pq;
        pq.emplace(0, s);
        while (!pq.empty()) {
            T d;
            int v;
            std::tie(d, v) = pq.top();
            pq.pop();
            if (dist[v] < d) continue;
            for (auto nx : to[v]) {
                T dnx = d + nx.second;
                if (dist[nx.first] > dnx) {
                    dist[nx.first] = dnx, prev[nx.first] = v;
                    pq.emplace(dnx, nx.first);
                }
            }
        }
    }

    // Bellman-Ford algorithm
    // Complexity: O(VE)
    bool BellmanFord(int s, int nb_loop) {
        assert(0 <= s and s < V);
        dist.assign(V, std::numeric_limits<T>::max());
        dist[s] = 0;
        prev.assign(V, INVALID);
        for (int l = 0; l < nb_loop; l++) {
            bool upd = false;
            for (int v = 0; v < V; v++) {
                if (dist[v] == std::numeric_limits<T>::max()) continue;
                for (auto nx : to[v]) {
                    T dnx = dist[v] + nx.second;
                    if (dist[nx.first] > dnx) {
                        dist[nx.first] = dnx, prev[nx.first] = v;
                        upd = true;
                    }
                }
            }
            if (!upd) return true;
        }
        return false;
    }

    void ZeroOneBFS(int s) {
        assert(0 <= s and s < V);
        dist.assign(V, std::numeric_limits<T>::max());
        dist[s] = 0;
        prev.assign(V, INVALID);
        std::deque<int> que;
        que.push_back(s);
        while (!que.empty()) {
            int v = que.front();
            que.pop_front();
            for (auto nx : to[v]) {
                T dnx = dist[v] + nx.second;
                if (dist[nx.first] > dnx) {
                    dist[nx.first] = dnx, prev[nx.first] = v;
                    if (nx.second) {
                        que.push_back(nx.first);
                    } else {
                        que.push_front(nx.first);
                    }
                }
            }
        }
    }

    // Warshall-Floyd algorithm
    // Complexity: O(E + V^3)
    std::vector<std::vector<T>> dist2d;
    void WarshallFloyd() {
        dist2d.assign(V, std::vector<T>(V, std::numeric_limits<T>::max()));
        for (int i = 0; i < V; i++) {
            dist2d[i][i] = 0;
            for (auto p : to[i]) dist2d[i][p.first] = min(dist2d[i][p.first], p.second);
        }
        for (int k = 0; k < V; k++) {
            for (int i = 0; i < V; i++) {
                if (dist2d[i][k] = std::numeric_limits<T>::max()) continue;
                for (int j = 0; j < V; j++) {
                    if (dist2d[k][j] = std::numeric_limits<T>::max()) continue;
                    dist2d[i][j] = min(dist2d[i][j], dist2d[i][k] + dist2d[k][j]);
                }
            }
        }
    }
};

// Shortest cycle detection of UNDIRECTED SIMPLE graphs
// Assumption: only two types of edges are permitted: weight = 0 or W ( > 0)
// Complexity: O(E)
// Verified: <https://codeforces.com/contest/1325/problem/E>
struct ShortestCycle01 {
    int V, E;
    int INVALID = -1;
    std::vector<std::vector<std::pair<int, int>>> to; // (nxt, weight)
    ShortestCycle01() = default;
    ShortestCycle01(int V) : V(V), E(0), to(V) {}
    void add_edge(int s, int t, int len) {
        assert(0 <= s and s < V);
        assert(0 <= t and t < V);
        assert(len >= 0);
        to[s].emplace_back(t, len);
        to[t].emplace_back(s, len);
        E++;
    }

    std::vector<lint> dist;
    std::vector<int> prev;
    // Find minimum length simple cycle which passes vertex `v`
    // - return: (LEN, (a, b))
    //   - LEN: length of the shortest cycles if exists, numeric_limits<int>::max() otherwise.
    //   - the cycle consists of vertices [v, ..., prev[prev[a]], prev[a], a, b, prev[b], prev[prev[b]], ..., v]
    std::pair<lint, std::pair<int, int>> Solve(int v) {
        assert(0 <= v and v < V);
        dist.assign(V, std::numeric_limits<lint>::max());
        dist[v] = 0;
        prev.assign(V, -1);
        using P = pair<lint, pint>;
        std::priority_queue<P, vector<P>, greater<P>> bfsq;
        std::vector<std::pair<std::pair<int, int>, int>> add_edge;
        bfsq.emplace(0, pint(v, -1));
        while (!bfsq.empty()) {
            auto [wnow, pp] = bfsq.top();
            auto [now, prv] = pp;
            bfsq.pop();
            for (auto nxt : to[now])
                if (nxt.first != prv) {
                    if (dist[nxt.first] == std::numeric_limits<lint>::max()) {
                        dist[nxt.first] = dist[now] + nxt.second;
                        prev[nxt.first] = now;
                        bfsq.emplace(dist[nxt.first], pint(nxt.first, now));
                    } else {
                        add_edge.emplace_back(std::make_pair(now, nxt.first), nxt.second);
                    }
                }
        }
        lint minimum_cycle = std::numeric_limits<lint>::max();
        int s = -1, t = -1;
        for (auto edge : add_edge) {
            int a = edge.first.first, b = edge.first.second;
            lint L = dist[a] + dist[b] + edge.second;
            if (L < minimum_cycle) minimum_cycle = L, s = a, t = b;
        }
        return std::make_pair(minimum_cycle, std::make_pair(s, t));
    }
};

// struct ShortestCycleOfUndirectedGraph {
//     int V, E;
//     std::vector<std::vector<std::pair<int, int>>> to;
//     ShortestCycleOfUndirectedGraph(int N) : V(N), E(0), to(N) {}
//     void add_edge(int s, int t, int len) {
//         assert(0 <= s and s < V);
//         assert(0 <= t and t < V);
//         assert(len >= 0);
//         to[s].emplace_back(t, len);
//         to[t].emplace_back(s, len);
//         E++;
//     }

//     std::array<std::vector<long long>, 2> dist;
//     std::array<std::vector<int>, 2> prev;
//     long long solve(int v) {
//         assert(0 <= v and v < V);
//         dist[0].assign(V, std::numeric_limits<long long>::max() / 2);
//         dist[1].assign(V, std::numeric_limits<long long>::max() / 2);
//         prev[0].assign(V, -1);
//         prev[1].assign(V, -1);
//         using P = std::pair<long long, int>;
//         std::priority_queue<P, std::vector<P>, std::greater<P>> pq;
//         while (!pq.empty()) {
//             long long wnow = pq.top().first;
//             int now = pq.top().second;
//             pq.pop();
//             if (dist[1][now] < wnow) continue;
//             for (const auto nxtp : to[now]) {
//                 int nxt = nxtp.first;
//                 if (prev1[now] != nxt and chmin(dist1[nxt], dist1[now] + nxtp.second)) prev1[nxt] = 
//             }
//         }
//     }
// };

void solve_dir(int N, int M) {
    vector<vector<pint>> to(N);
    while (M--) {
        int u, v, w;
        cin >> u >> v >> w;
        u--, v--;
        to[u].emplace_back(v, w);
    }
    lint ret = 1e18;
    REP(s, N) {
        ShortestPath<lint> graph(N + 1);
        REP(i, N) for (auto [j, w] : to[i]) {
            graph.add_edge(i, j, w);
            if (j == s) graph.add_edge(i, N, w);
        }
        graph.Dijkstra(s);
        if (graph.dist[N] < 1e18) chmin(ret, graph.dist[N]);
    }
    cout << (ret < 1e18 ? ret : -1) << '\n';
}

int main()
{
    int T, N, M;
    cin >> T >> N >> M;
    lint ret = 1e18;

    if (T == 1)
        solve_dir(N, M);
    else {
        ShortestCycle01 graph(N);
        while (M--) {
            int u, v, w;
            cin >> u >> v >> w;
            u--, v--;
            graph.add_edge(u, v, w);
        }
        REP(i, N) {
            chmin<lint>(ret, graph.Solve(i).first);
            dbg(ret);
            dbg(graph.dist);
            dbg(graph.prev);
        }
        cout << (ret < 1e18 ? ret : -1) << '\n';
    }
}