import copy N,M=map(int,input().split()) d=[[0 for j in range(N+1)] for i in range(N+1)] for i in range(M): a,b,c=map(int,input().split()) d[a][b]=d[b][a]=c inf=1<<60 #現在地、ゴール、コスト、チケット利用回数、履歴 def solve(location, goal, cost, ticket, history): cost2 = inf #print('solve', location, goal, cost, ticket) history2 = copy.copy(history) history2.add(location) if location==goal: return cost for i in range(1,N+1): if d[location][i]==0: continue if i in history2: continue cost2=min(cost2,solve(i,goal,cost+d[location][i],ticket,history2)) if ticket==0: cost2=min(cost2,solve(i,goal,cost,1,history2)) return cost2 for i in range(1,N+1): ans=solve(1, i, 0, 0, set()) + solve(1, i, 0, 1, set()) print(ans)