#include<iostream>
#include<cstdio>
using namespace std;
const int N=135;
struct tree{
	char left,right;
}a[N];
int n;
void dfs(char node){
	if(node=='*'||node==' ') return;
	cout<<node;
	dfs(a[node].left);
	dfs(a[node].right);
}
int main(){
	cin>>n;
	char NODE;
	cin>>NODE>>a[NODE].left>>a[NODE].right;
	for(int i=2;i<=n;i++){
		char h;
		cin>>h;
		cin>>a[h].left>>a[h].right;
	}
	dfs(NODE);
    return 0;
}

为什么样例不对却AC了呢