public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int N = sc . nextInt ( ) ;
  int M = sc . nextInt ( ) ;
  int [ ] s = new int [ 300002 ] ;
  int [ ] t = new int [ 300002 ] ;
  int [ ] x = new int [ 300002 ] ;
  int [ ] b = new int [ 300002 ] ;
  for ( int i = 0 ;
  i < M ;
  ++ i ) {
    s [ i ] = sc . nextInt ( ) ;
    t [ i ] = sc . nextInt ( ) ;
    int l = s [ i ] - 1 ;
    int r = t [ i ] - 1 ;
    b [ l ] ++ ;
    b [ r + 1 ] -- ;
  }
  for ( int i = 0 ;
  i < N + 1 ;
  ++ i ) {
    b [ i + 1 ] += b [ i ] ;
  }
  for ( int i = 1 ;
  i <= N ;
  i ++ ) {
    if ( b [ i - 1 ] == 1 ) {
      x [ i ] = 1 ;
    }
    else {
      x [ i ] = 0 ;
    }
  }
  for ( int i = 1 ;
  i < N ;
  i ++ ) {
    x [ i + 1 ] += x [ i ] ;
  }
  ArrayList < Integer > ans = new ArrayList < Integer > ( ) ;
  for ( int i = 0 ;
  i < M ;
  i ++ ) {
    if ( x [ t [ i ] ] - x [ s [ i ] - 1 ] == 0 ) {
      ans . add ( i + 1 ) ;
    }
  }
  System . out . println ( ans . size ( ) ) ;
  for ( int i = 0 ;
  i < ans . size ( ) ;
  i ++ ) {
    System . out . println ( ans . get ( i ) ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int N = sc . nextInt ( ) ; int M = sc . nextInt ( ) ; int [ ] s = new int [ 300002 ] ; int [ ] t = new int [ 300002 ] ; int [ ] x = new int [ 300002 ] ; int [ ] b = new int [ 300002 ] ; for ( int i = 0 ; i < M ; ++ i ) { s [ i ] = sc . nextInt ( ) ; t [ i ] = sc . nextInt ( ) ; int l = s [ i ] - 1 ; int r = t [ i ] - 1 ; b [ l ] ++ ; b [ r + 1 ] -- ; } for ( int i = 0 ; i < N + 1 ; ++ i ) { b [ i + 1 ] += b [ i ] ; } for ( int i = 1 ; i <= N ; i ++ ) { if ( b [ i - 1 ] == 1 ) { x [ i ] = 1 ; } else { x [ i ] = 0 ; } } for ( int i = 1 ; i < N ; i ++ ) { x [ i + 1 ] += x [ i ] ; } ArrayList < Integer > ans = new ArrayList < Integer > ( ) ; for ( int i = 0 ; i < M ; i ++ ) { if ( x [ t [ i ] ] - x [ s [ i ] - 1 ] == 0 ) { ans . add ( i + 1 ) ; } } System . out . println ( ans . size ( ) ) ; for ( int i = 0 ; i < ans . size ( ) ; i ++ ) { System . out . println ( ans . get ( i ) ) ; } }
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