#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
using namespace std;
vector<string>m;
char s[50];
int cnt = 1;
struct node
{
	int a[26];
	int f;
};
node tree[1000*100];

void build_tree()
{
	int root = 0;
	for(int i = 0; s[i]!= ‘\0‘; i ++)
	{
		if(tree[root].a[s[i]-‘a‘] == -1)
	    {
	    	tree[root].a[s[i]-‘a‘] = cnt ++;
	    }
	    root = tree[root].a[s[i]-‘a‘] ;
	}
	tree[root].f = 1;
}
void find_result()
{
	int root , root2;
	int flag ;
	for(int i = 0; i < (int)m.size(); i ++)
	{
		flag = 0;
		//cout << "test==="<<m[i]<<endl;
		root = 0;
		for(int j = 0; j < (int)m[i].size(); j ++)
		{
			if(tree[root].a[m[i][j]-‘a‘] != -1)
			{
				root = tree[root].a[m[i][j]-‘a‘];
				if(tree[root].f == 1)
				{
					//cout << "first paragram=="<<m[i][j]<<endl;
					root2 = 0;
					int k ;
					flag = 0;
					for(k = j + 1; k < (int)m[i].size(); k ++)
					{
						if(tree[root2].a[m[i][k]-‘a‘] == -1)
						{
							break;
						}
					    root2 = tree[root2].a[m[i][k]-‘a‘];
					}
					if(k == (int)m[i].size() && tree[root2].f == 1)
					{
						//cout << "second paragram===" <<m[i][k] <<endl;
						printf(m[i].c_str());
						printf("\n");
						//cout << m[i]<<endl;
						flag = 1;
					}
				}
			}     
			if(flag)break;
		}
	}
	return ;
}
int main()
{
	for(int i = 0; i < 1000*100; i ++)
	{
		tree[i].f = 0;
		for(int j = 0; j < 26; j ++)
		{
			tree[i].a[j] = -1;
		}
	}
	string ss;
	int n;
	while(scanf("%s",s)!=EOF)
	{
		ss = s;
		n = m.size();
		build_tree();
		if(n == 0)
		{
			m.push_back(ss);
		}
		else if(ss.compare(m[n-1]))
		{
			m.push_back(ss);
		}
	}
	find_result();
	return 0;
}