public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int a = sc . nextInt ( ) ;
  for ( int i = 0 ;
  i < a ;
  i ++ ) {
    int n = sc . nextInt ( ) ;
    int [ ] arr = new int [ 26 ] ;
    for ( int j = 0 ;
    j < n ;
    j ++ ) {
      String s = sc . next ( ) ;
      for ( int k = 0 ;
      k < s . length ( ) ;
      k ++ ) {
        int as = s . charAt ( k ) - 'a' ;
        arr [ as ] += 1 ;
      }
    }
    boolean c = false ;
    for ( int j = 0 ;
    j < 26 ;
    j ++ ) {
      if ( arr [ j ] % n != 0 ) {
        c = true ;
        break ;
      }
      else {
        c = false ;
      }
    }
    System . out . println ( ! c ? "YES" : "NO" ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int a = sc . nextInt ( ) ; for ( int i = 0 ; i < a ; i ++ ) { int n = sc . nextInt ( ) ; int [ ] arr = new int [ 26 ] ; for ( int j = 0 ; j < n ; j ++ ) { String s = sc . next ( ) ; for ( int k = 0 ; k < s . length ( ) ; k ++ ) { int as = s . charAt ( k ) - ' a ' ; arr [ as ] += 1 ; } } boolean c = false ; for ( int j = 0 ; j < 26 ; j ++ ) { if ( arr [ j ] % n != 0 ) { c = true ; break ; } else { c = false ; } } System . out . println ( ! c ? " YES " : " NO " ) ; } }
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