public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int m = sc . nextInt ( ) ;
  int [ ] arr = new int [ n + 1 ] ;
  int [ ] arrS = new int [ m + 1 ] ;
  int [ ] arrT = new int [ m + 1 ] ;
  for ( int i = 1 ;
  i <= m ;
  i ++ ) {
    arrS [ i ] = sc . nextInt ( ) ;
    arrT [ i ] = sc . nextInt ( ) ;
    arr [ arrS [ i ] ] ++ ;
    if ( arrT [ i ] != n ) {
      arr [ arrT [ i ] + 1 ] -- ;
    }
  }
  int [ ] arrX = new int [ n + 1 ] ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    arr [ i ] += arr [ i - 1 ] ;
    arrX [ i ] += arrX [ i - 1 ] ;
    if ( arr [ i ] < 2 ) {
      arrX [ i ] ++ ;
    }
  }
  int count = 0 ;
  ArrayList < Integer > list = new ArrayList < > ( ) ;
  for ( int i = 1 ;
  i <= m ;
  i ++ ) {
    if ( arrX [ arrT [ i ] ] - arrX [ arrS [ i ] - 1 ] == 0 ) {
      count ++ ;
      list . add ( i ) ;
    }
  }
  StringBuilder sb = new StringBuilder ( ) ;
  sb . append ( count ) . append ( "\n" ) ;
  for ( int x : list ) {
    sb . append ( x ) . append ( "\n" ) ;
  }
  System . out . print ( sb ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int m = sc . nextInt ( ) ; int [ ] arr = new int [ n + 1 ] ; int [ ] arrS = new int [ m + 1 ] ; int [ ] arrT = new int [ m + 1 ] ; for ( int i = 1 ; i <= m ; i ++ ) { arrS [ i ] = sc . nextInt ( ) ; arrT [ i ] = sc . nextInt ( ) ; arr [ arrS [ i ] ] ++ ; if ( arrT [ i ] != n ) { arr [ arrT [ i ] + 1 ] -- ; } } int [ ] arrX = new int [ n + 1 ] ; for ( int i = 1 ; i <= n ; i ++ ) { arr [ i ] += arr [ i - 1 ] ; arrX [ i ] += arrX [ i - 1 ] ; if ( arr [ i ] < 2 ) { arrX [ i ] ++ ; } } int count = 0 ; ArrayList < Integer > list = new ArrayList < > ( ) ; for ( int i = 1 ; i <= m ; i ++ ) { if ( arrX [ arrT [ i ] ] - arrX [ arrS [ i ] - 1 ] == 0 ) { count ++ ; list . add ( i ) ; } } StringBuilder sb = new StringBuilder ( ) ; sb . append ( count ) . append ( " \n " ) ; for ( int x : list ) { sb . append ( x ) . append ( " \n " ) ; } System . out . print ( sb ) ; }
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