1 #include <iostream>
 2 #include <algorithm>
 3 #include <cstring>
 4 #include <cstdio>
 5 #include <vector>
 6 using namespace std;
 7 const int maxn=1e5+5;
 8 const int INF=1e9+5;
 9 struct A
10 {
11     int v,next;
12 }e[maxn];
13 int head[maxn],tot;
14 int d[maxn][3];
15 int n,a,b;
16 template <class t>void red(t &x)
17 {
18     x=0;
19     int w=1;
20     char ch=getchar();
21     while(ch<'0'||ch>'9')
22     {
23         if(ch=='-')
24             w=-1;
25         ch=getchar();
26     }
27     while(ch>='0'&&ch<='9')
28     {
29         x=(x<<3)+(x<<1)+ch-'0';
30         ch=getchar();
31     }
32     x*=w;
33 }
34 void input()
35 {
36     freopen("input.txt","r",stdin);
37     //freopen("output.txt","w",stdout);
38 }
39 void add(int x,int y)
40 {
41     e[++tot].v=y;
42     e[tot].next=head[x];
43     head[x]=tot;
44 }
45 void dfs(int u,int fa)
46 {
47     d[u][0]=1;
48     d[u][1]=0;
49     d[u][2]=INF;
50     for(int i=head[u];i;i=e[i].next)
51     {
52         int v=e[i].v;
53         if(v==fa)
54             continue;
55         dfs(v,u);
56         d[u][0]+=min(d[v][0],d[v][1]);//u
57         if(d[v][2]>=INF)
58             d[u][1]=INF;
59         else
60             d[u][1]+=d[v][2];//f
61     }
62     for(int i=head[u];i;i=e[i].next)
63     {
64         int v=e[i].v;
65         if(v==fa)
66             continue;
67     //    if(d[v][2]<INF)
68         d[u][2]=min(d[u][2],d[u][1]+d[v][0]-d[v][2]);
69     }
70 }
71 int main()
72 {
73     //input();
74     while(1)
75     {
76         red(n);
77         if(!n)
78             red(n);
79         if(n==-1)
80             break;
81         tot=0;
82         memset(head,0,sizeof(head));
83         //memset(d,0x3f,sizeof(d));
84         for(int i=1;i<n;++i)
85         {
86             red(a);
87             red(b);
88             add(a,b);
89             add(b,a);
90         }
91         dfs(1,0);
92         printf("%d\n",min(d[1][0],d[1][2]));
93     }
94     return 0;
95 }