1 #include "bits/stdc++.h"

 2 using namespace std;

 3 const int MAX=1e6+5;

 4 int n;

 5 int tot,head[MAX],adj[MAX],nxt[MAX],wei[MAX];

 6 int val[MAX];

 7 void addedge(int u,int v,int w){

 8     tot++;

 9     adj[tot]=v;

10     wei[tot]=w;

11     nxt[tot]=head[u];

12     head[u]=tot;

13 }

14 void dfs(int x,int fa){

15     int i,j;

16     for (i=head[x];i;i=nxt[i]){

17         if (adj[i]==fa) continue;

18         val[adj[i]]=val[x]^wei[i];

19         dfs(adj[i],x);

20     }

21 }

22 struct Str{

23     int str[MAX][2],cnt;

24     bool vis[MAX];

25     Str(){

26         memset(str,0,sizeof(str));

27         cnt=0;

28         memset(vis,false,sizeof(vis));

29     }

30     void insert(int x){

31         int i,j,p=0;

32         bool zt;

33         for (i=30;i>=0;i--){

34             zt=(1<<i)&x;

35             if (str[p][zt]==0){

36                 str[p][zt]=++cnt;

37                 p=cnt;

38             }

39             else p=str[p][zt];

40         }

41         vis[p]=true;

42     }

43     int check(int v){

44         int i,j,p=0,ans=0;

45         bool zt;

46         for (i=30;i>=0;i--){

47             zt=v&(1<<i);

48             if (str[p][!zt]){

49                 ans+=(1<<i);

50                 p=str[p][!zt];

51             }

52             else p=str[p][zt];

53 //            cout<<p<<endl;

54         }

55 //        cout<<v<<' '<<ans<<endl;

56         return ans;

57     }

58 }ss;

59 int main(){

60     int i,j,u,v,w,ans=0;

61     scanf("%d",&n);

62     memset(head,0,sizeof(head));

63     memset(val,0,sizeof(val));

64     for (i=1;i<n;i++){

65         scanf("%d%d%d",&u,&v,&w);

66         addedge(u,v,w);

67         addedge(v,u,w);

68     }

69     dfs(1,0);

70 //    for (i=1;i<=n;i++)

71 //        cout<<i<<" : "<<val[i]<<endl;

72     for (i=1;i<=n;i++)

73         ss.insert(val[i]);

74     for (i=1;i<=n;i++)

75         ans=max(ans,ss.check(val[i]));

76     printf("%d\n",ans);

77     return 0;

78 }