#include <iostream>
using namespace std;
int main( ) {
int n,tablica[ n] ;
cin >> n;
cin >> tablica[ 0 ]
for ( int k = 0 ; k <= n; k++ ) {
cin >> tablica[ k] ;
}
cout << tablica[ 0 ] << " " ;
for ( int j = 0 ; j <= n; j++ ) {
if ( j % 2 == 0 ) {
cout << tablica[ j] << " " ;
}
}
cout << endl;
for ( int j = 0 ; j <= n; j++ ) {
if ( j % 2 ! = 0 ) {
cout << tablica[ j] << " " ;
}
}
}
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