#include <cstdio>
struct node{
        int left;
        int right;
}Node[30];
char s[30];
int main(){
        int zhan[30],n, top = 0, hash[30] = {0}, root;//hash for root
        scanf("%d",&n);//read n
        for(int i = 0;i < n;++i){
                char a, l, r;
                scanf("%s", s);
                a = s[0], l = s[1], r = s[2];
                if(a == '*') continue;
                a -= 'a';
                if(l != '*')    hash[l - 'a'] = 1, Node[a].left = l - 'a';
                else    Node[a].left = -1;
                if(r != '*')    hash[r - 'a'] = 1, Node[a].right = r- 'a';
                else    Node[a].right = -1;
        }//read all data
        for(int i = 0;i < n;++i)
                if(!hash[i])    {root = i;break;}
        zhan[top++] = root;     //ruzhan root
        while(top){
                char tmp = zhan[--top];
                printf("%c", tmp + 'a');
                if(Node[tmp].right != -1) zhan[top++] = Node[tmp].right;
                if(Node[tmp].left != -1) zhan[top++] = Node[tmp].left;
        }
        return 0;
}