#include<iostream>
using namespace std;

typedef struct tree
{
    char data;
    struct tree* lchild;
    struct tree* rchild;
}Tree,*BTree;

int n;
string s0,s1;

BTree creat()
{
    char data;
    BTree T;

    for(int i=0;i<s1.length();i++)
    {
        data=s1[i];
        if(data=='*') return NULL;
        else
        {
            T=new Tree;
            T->data=data;
            T->lchild=creat();
            T->rchild=creat();
        }
    }
    return T;
}

void first(BTree T)
{
    if(T!=NULL)
    {
        cout << T->data;
        first(T->lchild);
        first(T->rchild);
    }
}

int main()
{
    cin >> n;
    for(int i=1;i<=n;i++)
    {
        cin >> s0;
        s1+=s0;
    }
    BTree s;
    s=creat();
    first(s);
    return 0;
}