#include <iostream>
#include <list>
using namespace std;
int main( )
{ int a,b;
while ( cin >> a)
{ list < int > lista;
while ( cin >> b)
{
for ( list< int > :: iterator i= lista.begin ( ) ; i! = lista.end ( ) ; i++ )
if ( * i== b) i= lista.erase ( i) ; lista.push_front ( b) ; if ( cin .peek ( ) == '\n ' || cin .peek ( ) == EOF ) break ;
}
lista.sort ( ) ;
lista.reverse ( ) ;
if ( lista.size ( ) < a) cout << '-' << endl;
else {
list< int > :: iterator i= lista.begin ( ) ;
for ( int k= 1 ; k< a; k++ )
i++ ;
cout << * i<< endl; } lista.clear ( ) ;
}
return 0 ;
}
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