#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <cstdio>

#include <string>

#include <cstdlib>

#include <cmath>

#include <iostream>

#include <cstring>

#include <set>

#include <queue>

#include <algorithm>

#include <vector>

#include <map>

#include <cctype>

#include <cmath>

#include <stack>

#include <sstream>

#define debug() puts("++++");

#define gcd(a, b) __gcd(a, b)

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define freopenr freopen("in.txt", "r", stdin)

#define freopenw freopen("out.txt", "w", stdout)

using namespace std;

typedef long long LL;

typedef unsigned long long ULL;

typedef pair<int, int> P;

const int INF = 0x3f3f3f3f;

const LL LNF = 1e16;

const double inf = 0x3f3f3f3f3f3f;

const double PI = acos(-1.0);

const double eps = 1e-8;

const int maxn = 10 + 5;

const int mod = 100000000;

const int dr[] = {-1, 0, 1, 0};

const int dc[] = {0, 1, 0, -1};

const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};

int n, m;

const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

inline bool is_in(int r, int c){

  return r >= 0 && r < n && c >= 0 && c < m;

}

int G[10][10];

int dp[60000][10];

int f[10];

struct Node{

  int state, pos;

  Node(int s, int p) : state(s), pos(p) { }

};

int calc(int state, int i){

  return state + f[i];

}

bool judge(int state){

  for(int i = 0; i < n; ++i, state /= 3)

    if(state % 3 == 0)  return false;

  return true;

}

int bfs(){

  memset(dp, INF, sizeof dp);

  queue<Node> q;

  for(int i = 0; i < n; ++i){

    dp[calc(0, i)][i] = 0;

    q.push(Node(calc(0, i), i));

  }

  int ans = INF;

  if(n == 1)  return 0;

  while(!q.empty()){

    Node u = q.front();  q.pop();

    int state = u.state;

    for(int i = 0; i < n; ++i)  if(G[u.pos][i] != INF){

      if(state / f[i] % 3 == 2)  continue;

      int newstate = calc(state, i);

      int neww = dp[state][u.pos] + G[u.pos][i];

      if(dp[newstate][i] <= neww)  continue;  //去年无用的状态，要不然可能会超时或者超内存

      dp[newstate][i] = neww;

      if(judge(newstate)){

        ans = min(ans, dp[newstate][i]);

        continue;

      }

      else q.push(Node(newstate, i));

    }

  }

  return ans;

}

int main(){

  f[0] = 1;

  for(int i = 1; i < 10; ++i)  f[i] = f[i-1] * 3;

  while(scanf("%d %d", &n, &m) == 2){

    memset(G, INF, sizeof G);

    for(int i = 0; i < m; ++i){

      int a, b, c;

      scanf("%d %d %d", &a, &b, &c);

      --a, --b;

      G[a][b] = G[b][a] = min(G[a][b], c);

    }

    int ans = bfs();

    printf("%d\n", ans == INF ? -1 : ans);

  }

  return 0;

}