1 #include <cstdio>
 2 #include <cstring>
 3 #include <cmath>
 4 #include <queue>
 5 #include <algorithm>
 6 
 7 using namespace std;
 8 
 9 #define MAXN 110
10 #define INF 0x3f3f3f3f
11 #define MAX(a,b) (a>b?a:b)
12 #define MIN(a,b) (a<b?a:b)
13 #define ABS(m) (m<0?-m:m)
14 typedef long long LL;
15 
16 int n,m,ans;
17 int Update[MAXN][MAXN],Road[MAXN];
18 int dis[MAXN][MAXN],e[MAXN][MAXN];
19 
20 void Init()
21 {
22     memset(e,0x3f,sizeof(e));
23     int i,u,v,d;
24     for(i=1;i<=m;++i){
25         scanf("%d%d%d",&u,&v,&d);
26         e[u][v]=min(e[u][v],d);
27         e[v][u]=e[u][v];
28     }
29 }
30 
31 void GetRoad(int i,int j)
32 {
33     if(!Update[i][j]) Road[++Road[0]]=i;
34     else GetRoad(i,Update[i][j]),GetRoad(Update[i][j],j);
35 }
36 
37 void Floyd()
38 {
39     int i,j,k; ans=INF;
40     memcpy(dis,e,sizeof(e));
41     memset(Update,0,sizeof(Update));
42     for(k=1;k<=n;++k){
43         for(i=1;i<k;++i)
44             for(j=i+1;j<k;++j)
45                 if(0LL+dis[i][j]+e[i][k]+e[k][j]<ans){
46                     ans=dis[i][j]+e[i][k]+e[k][j];
47                     Road[0]=0; GetRoad(i,j);
48                     Road[++Road[0]]=j;
49                     Road[++Road[0]]=k;
50                 }
51         for(i=1;i<=n;++i)
52             for(j=1;j<=n;++j)
53                 if(dis[i][k]+dis[k][j]<dis[i][j]){
54                     dis[i][j]=dis[i][k]+dis[k][j];
55                     Update[i][j]=k;
56                 }
57     }
58     if(ans==INF) printf("No solution.\n");
59     else{
60         for(i=1;i<Road[0];++i) printf("%d ",Road[i]);
61         printf("%d\n",Road[i]);
62     }
63 }
64 
65 int main()
66 {
67     while(scanf("%d",&n),n!=-1){
68         scanf("%d",&m);
69         Init();
70         Floyd();
71     }
72     return 0;
73 }