public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int work = sc . nextInt ( ) ;
  int breakLength = sc . nextInt ( ) ;
  int [ ] [ ] customers = new int [ n ] [ ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) customers [ i ] = new int [ ] {
    sc . nextInt ( ) , sc . nextInt ( ) };
    sc . close ( ) ;
    if ( n == 0 ) {
      System . out . println ( work / breakLength ) ;
      sc . close ( ) ;
      return ;
    }
    int num = 0 ;
    int time = 0 ;
    for ( int i = 0 ;
    i < n ;
    i ++ ) if ( customers [ i ] [ 0 ] - time >= breakLength ) {
      time += breakLength ;
      num ++ ;
      i -- ;
    }
    else time = customers [ i ] [ 0 ] + customers [ i ] [ 1 ] ;
    num += ( work - time ) / breakLength ;
    System . out . println ( num ) ;
  }
  
public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int work = sc . nextInt ( ) ; int breakLength = sc . nextInt ( ) ; int [ ] [ ] customers = new int [ n ] [ ] ; for ( int i = 0 ; i < n ; i ++ ) customers [ i ] = new int [ ] { sc . nextInt ( ) , sc . nextInt ( ) } ; sc . close ( ) ; if ( n == 0 ) { System . out . println ( work / breakLength ) ; sc . close ( ) ; return ; } int num = 0 ; int time = 0 ; for ( int i = 0 ; i < n ; i ++ ) if ( customers [ i ] [ 0 ] - time >= breakLength ) { time += breakLength ; num ++ ; i -- ; } else time = customers [ i ] [ 0 ] + customers [ i ] [ 1 ] ; num += ( work - time ) / breakLength ; System . out . println ( num ) ; }
(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: (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 (identifier)) dimensions: (dimensions)))) (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: (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (array_creation_expression type: (integral_type) dimensions: (dimensions) value: (array_initializer (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (return_statement))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (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: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (identifier)) right: (identifier))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (update_expression (identifier))) (expression_statement (update_expression (identifier)))) alternative: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal))))))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (identifier)))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))