1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 #define MS(a) memset(a,0,sizeof(a))
 5 #define MP make_pair
 6 #define PB push_back
 7 const int INF = 0x3f3f3f3f;
 8 const ll INFLL = 0x3f3f3f3f3f3f3f3fLL;
 9 inline ll read(){
10     ll x=0,f=1;char ch=getchar();
11     while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
12     while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
13     return x*f;
14 }
15 //
16 const int maxn = 1e5+10;
17
18 int n,vis[20],g[20][20],cnt;
19
20 bool two(int s){
21     for(int i=0; i<n; i++){
22         if(s & (1<<i)) continue;
23         int cnt = 0;
24         for(int j=0; j<n; j++){
25             if(s & (1<<j)) continue;
26             if(g[i][j] && i!=j) cnt++;
27         }
28         if(cnt > 2) return true;
29     }
30
31     return false;
32 }
33
34 bool dfs(int s,int now,int fa){
35     vis[now] = 1;
36     for(int i=0; i<n; i++){
37         if(!g[now][i] || s&(1<<i) || i==fa) continue;
38         if(vis[i]) return true;
39         if(dfs(s,i,now)) return true;
40     }
41     return false;
42 }
43
44 bool circle(int s){
45     for(int i=0; i<n; i++){
46         if(s & (1<<i)) continue;
47         if(vis[i]) continue;
48         cnt++;
49         if(dfs(s,i,-1)) return true;
50     }
51     return false;
52 }
53
54 int cal(int x){
55     return x==0 ? 0 : cal(x/2)+(x%2);
56 }
57
58 int main(){
59     int cas = 1;
60     while(scanf("%d",&n) && n){
61         MS(g);
62         int u,v;
63         while(scanf("%d%d",&u,&v)){
64             if(u==-1 && v==-1) break;
65             g[u-1][v-1] = g[v-1][u-1] = 1;
66         }
67         int s = (1<<n);
68         int ans = INF;
69         for(int i=0; i<s; i++){
70             MS(vis); cnt=0;  // cnt 表示 如果剩下的环中，没有连成圈的， 那有几条链
71             if(two(i) || circle(i)) continue;
72             if(cal(i) >= cnt-1) // 如果拆下来的环  大于链数-1  才能连成一条链
73                 ans = min(ans,cal(i));
74         }
75         printf("Set %d: Minimum links to open is %d\n",cas++,ans);
76     }
77
78     return 0;
79 }