public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int m = sc . nextInt ( ) ;
  int [ ] wrc = new int [ n + 1 ] ;
  int [ ] wrn = new int [ n + 1 ] ;
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    int s = sc . nextInt ( ) ;
    int t = sc . nextInt ( ) ;
    wrc [ s - 1 ] += 1 ;
    wrc [ t ] -= 1 ;
    wrn [ s - 1 ] += i ;
    wrn [ t ] -= i ;
  }
  boolean [ ] brni = new boolean [ m ] ;
  Arrays . fill ( brni , true ) ;
  int linecnt = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    wrc [ i + 1 ] += wrc [ i ] ;
    wrn [ i + 1 ] += wrn [ i ] ;
  }
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( wrc [ i ] == 1 && brni [ wrn [ i ] ] ) {
      brni [ wrn [ i ] ] = false ;
      linecnt ++ ;
    }
  }
  System . out . println ( m - linecnt ) ;
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    if ( brni [ i ] ) {
      System . out . println ( i + 1 ) ;
    }
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int m = sc . nextInt ( ) ; int [ ] wrc = new int [ n + 1 ] ; int [ ] wrn = new int [ n + 1 ] ; for ( int i = 0 ; i < m ; i ++ ) { int s = sc . nextInt ( ) ; int t = sc . nextInt ( ) ; wrc [ s - 1 ] += 1 ; wrc [ t ] -= 1 ; wrn [ s - 1 ] += i ; wrn [ t ] -= i ; } boolean [ ] brni = new boolean [ m ] ; Arrays . fill ( brni , true ) ; int linecnt = 0 ; for ( int i = 0 ; i < n ; i ++ ) { wrc [ i + 1 ] += wrc [ i ] ; wrn [ i + 1 ] += wrn [ i ] ; } for ( int i = 0 ; i < n ; i ++ ) { if ( wrc [ i ] == 1 && brni [ wrn [ i ] ] ) { brni [ wrn [ i ] ] = false ; linecnt ++ ; } } System . out . println ( m - linecnt ) ; for ( int i = 0 ; i < m ; i ++ ) { if ( brni [ i ] ) { System . out . println ( i + 1 ) ; } } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (decimal_integer_literal))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (identifier))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (identifier))))) (local_variable_declaration type: (array_type element: (boolean_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (boolean_type) dimensions: (dimensions_expr (identifier))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (true)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (array_access array: (identifier) index: (identifier)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (array_access array: (identifier) index: (identifier)))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal)) right: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))))) consequence: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))) right: (false))) (expression_statement (update_expression (identifier))))))) (expression_statement (method_invocation object: (field_access 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