public static void main ( String args [ ] ) {
  FastScanner input = new FastScanner ( ) ;
  long n = input . nextLong ( ) ;
  for ( long i = 1 ;
  i <= 90 ;
  i ++ ) {
    long d = ( i * i ) + ( 4 * n ) ;
    long x1 = ( long ) Math . sqrt ( d ) ;
    if ( x1 * x1 == d ) {
      long x = ( - i + x1 ) / 2 ;
      long sumof = sumOfdigit ( x ) ;
      if ( sumof == i ) {
        System . out . println ( x ) ;
        return ;
      }
      x = ( - i - x1 ) / 2 ;
      sumof = sumOfdigit ( x ) ;
      if ( sumof == i ) {
        System . out . println ( x ) ;
        return ;
      }
    }
  }
  System . out . println ( "-1" ) ;
}

public static void main ( String args [ ] ) { FastScanner input = new FastScanner ( ) ; long n = input . nextLong ( ) ; for ( long i = 1 ; i <= 90 ; i ++ ) { long d = ( i * i ) + ( 4 * n ) ; long x1 = ( long ) Math . sqrt ( d ) ; if ( x1 * x1 == d ) { long x = ( - i + x1 ) / 2 ; long sumof = sumOfdigit ( x ) ; if ( sumof == i ) { System . out . println ( x ) ; return ; } x = ( - i - x1 ) / 2 ; sumof = sumOfdigit ( x ) ; if ( sumof == i ) { System . out . println ( x ) ; return ; } } } System . out . println ( " - 1" ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier) dimensions: (dimensions))) 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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (parenthesized_expression (binary_expression left: (decimal_integer_literal) right: (identifier)))))) (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 (identifier)))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (identifier))) consequence: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (parenthesized_expression (binary_expression left: (unary_expression operand: (identifier)) right: (identifier))) right: (decimal_integer_literal)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation name: (identifier) arguments: (argument_list (identifier))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (return_statement))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (parenthesized_expression (binary_expression left: (unary_expression operand: (identifier)) right: (identifier))) right: (decimal_integer_literal)))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation name: (identifier) arguments: (argument_list (identifier))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (return_statement))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))