public static void main ( String args [ ] ) throws IOException {
  Scanner sc = new Scanner ( System . in ) ;
  int t = sc . nextInt ( ) ;
  while ( t -- > 0 ) {
    int n = sc . nextInt ( ) ;
    int x = sc . nextInt ( ) ;
    int [ ] ar = new int [ n ] ;
    int sum = 0 ;
    for ( int i = 0 ;
    i < n ;
    i ++ ) {
      ar [ i ] = sc . nextInt ( ) ;
      sum += ar [ i ] ;
    }
    int max = Integer . MIN_VALUE ;
    int sum1 = sum ;
    for ( int i = 0 ;
    i < n ;
    i ++ ) {
      if ( sum % x != 0 ) {
        max = n - i ;
        break ;
      }
      else {
        sum -= ar [ i ] ;
      }
    }
    for ( int j = n - 1 ;
    j >= 0 ;
    j -- ) {
      if ( sum1 % x != 0 ) {
        if ( j + 1 > max ) {
          max = j + 1 ;
          break ;
        }
      }
      else {
        sum1 -= ar [ j ] ;
      }
    }
    if ( max == Integer . MIN_VALUE ) {
      System . out . println ( - 1 ) ;
    }
    else {
      System . out . println ( max ) ;
    }
  }
}

public static void main ( String args [ ] ) throws IOException { Scanner sc = new Scanner ( System . in ) ; int t = sc . nextInt ( ) ; while ( t -- > 0 ) { int n = sc . nextInt ( ) ; int x = sc . nextInt ( ) ; int [ ] ar = new int [ n ] ; int sum = 0 ; for ( int i = 0 ; i < n ; i ++ ) { ar [ i ] = sc . nextInt ( ) ; sum += ar [ i ] ; } int max = Integer . MIN_VALUE ; int sum1 = sum ; for ( int i = 0 ; i < n ; i ++ ) { if ( sum % x != 0 ) { max = n - i ; break ; } else { sum -= ar [ i ] ; } } for ( int j = n - 1 ; j >= 0 ; j -- ) { if ( sum1 % x != 0 ) { if ( j + 1 > max ) { max = j + 1 ; break ; } } else { sum1 -= ar [ j ] ; } } if ( max == Integer . MIN_VALUE ) { System . out . println ( - 1 ) ; } else { System . out . println ( max ) ; } } }
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