public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int m = sc . nextInt ( ) ;
  lists = new ArrayList [ n + 1 ] ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    lists [ i ] = new ArrayList < Integer > ( ) ;
  }
  int [ ] a = new int [ m ] ;
  int [ ] b = new int [ m ] ;
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    a [ i ] = sc . nextInt ( ) ;
    b [ i ] = sc . nextInt ( ) ;
    lists [ a [ i ] ] . add ( b [ i ] ) ;
    lists [ b [ i ] ] . add ( a [ i ] ) ;
  }
  int count = 0 ;
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    boolean [ ] test = new boolean [ n + 1 ] ;
    Arrays . fill ( test , false ) ;
    search ( 1 , a [ i ] , b [ i ] , test ) ;
    if ( ! isAllTrue ( test ) ) {
      count ++ ;
    }
  }
  System . out . print ( count ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int m = sc . nextInt ( ) ; lists = new ArrayList [ n + 1 ] ; for ( int i = 1 ; i <= n ; i ++ ) { lists [ i ] = new ArrayList < Integer > ( ) ; } int [ ] a = new int [ m ] ; int [ ] b = new int [ m ] ; for ( int i = 0 ; i < m ; i ++ ) { a [ i ] = sc . nextInt ( ) ; b [ i ] = sc . nextInt ( ) ; lists [ a [ i ] ] . add ( b [ i ] ) ; lists [ b [ i ] ] . add ( a [ i ] ) ; } int count = 0 ; for ( int i = 0 ; i < m ; i ++ ) { boolean [ ] test = new boolean [ n + 1 ] ; Arrays . fill ( test , false ) ; search ( 1 , a [ i ] , b [ i ] , test ) ; if ( ! isAllTrue ( test ) ) { count ++ ; } } System . out . print ( count ) ; }
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