public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int k = Integer . parseInt ( sc . next ( ) ) ;
  String s = sc . next ( ) ;
  int [ ] count = new int [ 26 ] ;
  for ( int i = 0 ;
  i < s . length ( ) ;
  i ++ ) {
    count [ s . charAt ( i ) - 'a' ] ++ ;
  }
  for ( int i : count ) {
    if ( i % k != 0 ) {
      System . out . println ( "-1" ) ;
      return ;
    }
  }
  StringBuilder ans = new StringBuilder ( s . length ( ) ) ;
  for ( char c = 'a' ;
  c <= 'z' ;
  c ++ ) {
    int times = count [ c - 'a' ] / k ;
    while ( times -- > 0 ) {
      ans . append ( c ) ;
    }
  }
  String appender = ans . toString ( ) ;
  for ( int i = 1 ;
  i < k ;
  i ++ ) {
    ans . append ( appender ) ;
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int k = Integer . parseInt ( sc . next ( ) ) ; String s = sc . next ( ) ; int [ ] count = new int [ 26 ] ; for ( int i = 0 ; i < s . length ( ) ; i ++ ) { count [ s . charAt ( i ) - ' a ' ] ++ ; } for ( int i : count ) { if ( i % k != 0 ) { System . out . println ( " - 1" ) ; return ; } } StringBuilder ans = new StringBuilder ( s . length ( ) ) ; for ( char c = ' a ' ; c <= ' z ' ; c ++ ) { int times = count [ c - ' a ' ] / k ; while ( times -- > 0 ) { ans . append ( c ) ; } } String appender = ans . toString ( ) ; for ( int i = 1 ; i < k ; i ++ ) { ans . append ( appender ) ; } System . out . println ( ans ) ; }
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