public static void main ( String [ ] args ) {
  FastScanner input = new FastScanner ( ) ;
  long n = input . nextInt ( ) * 2 ;
  long x1 = input . nextInt ( ) ;
  long y1 = input . nextInt ( ) ;
  long x2 = input . nextInt ( ) ;
  long y2 = input . nextInt ( ) ;
  long ans = ( long ) Math . ceil ( ( Math . sqrt ( ( ( x2 - x1 ) * ( x2 - x1 ) ) + ( ( y1 - y2 ) * ( y1 - y2 ) ) ) ) / n ) ;
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { FastScanner input = new FastScanner ( ) ; long n = input . nextInt ( ) * 2 ; long x1 = input . nextInt ( ) ; long y1 = input . nextInt ( ) ; long x2 = input . nextInt ( ) ; long y2 = input . nextInt ( ) ; long ans = ( long ) Math . ceil ( ( Math . sqrt ( ( ( x2 - x1 ) * ( x2 - x1 ) ) + ( ( y1 - y2 ) * ( y1 - y2 ) ) ) ) / n ) ; System . out . println ( ans ) ; }
(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)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))) (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: (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: (cast_expression type: (integral_type) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (parenthesized_expression (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))))) right: (parenthesized_expression (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (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))))))