public static void main ( String [ ] args ) throws IOException {
  FastReader sc = new FastReader ( ) ;
  PrintWriter out = new PrintWriter ( System . out ) ;
  int n = sc . nextInt ( ) ;
  int k = sc . nextInt ( ) ;
  int diff = 0 ;
  while ( n -- > 0 ) {
    int i = sc . nextInt ( ) , j = sc . nextInt ( ) ;
    diff += j - i + 1 ;
  }
  int m = ( diff + k - 1 ) / k ;
  out . println ( k * m - diff ) ;
  out . close ( ) ;
}

public static void main ( String [ ] args ) throws IOException { FastReader sc = new FastReader ( ) ; PrintWriter out = new PrintWriter ( System . out ) ; int n = sc . nextInt ( ) ; int k = sc . nextInt ( ) ; int diff = 0 ; while ( n -- > 0 ) { int i = sc . nextInt ( ) , j = sc . nextInt ( ) ; diff += j - i + 1 ; } int m = ( diff + k - 1 ) / k ; out . println ( k * m - diff ) ; out . close ( ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list)))) (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: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (while_statement condition: (parenthesized_expression (binary_expression left: (update_expression (identifier)) right: (decimal_integer_literal))) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) right: (identifier)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (identifier))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))