#include <iostream>
#include <string>
#include <map>
using namespace std;
map < string , int > mp;
string str[50005];
int main ()
{
int n = 0;
while ( cin >> str[n] )
mp[ str[n++] ] = 1;
for ( int i = 0; i < n; ++ i )
{
unsigned len = str[i].size ();
for ( unsigned j = 1; j < len; ++ j )
{
string s1 ( str[i], 0, j );//0开始长度为j
string s2 ( str[i], j );//初始位置在j
if ( mp[s1] == 1 && mp[s2] == 1 )
{
cout << str[i] << endl;
break;
}
}
}
return 0;
}