public static void main ( String [ ] args ) {
  FastReader sc = new FastReader ( ) ;
  long n = sc . nextLong ( ) ;
  long k = sc . nextLong ( ) ;
  long x = ( long ) ( - 3 + ( Math . sqrt ( 9 + 8 * ( n + k ) ) ) ) / 2 ;
  System . out . println ( n - x ) ;
}

public static void main ( String [ ] args ) { FastReader sc = new FastReader ( ) ; long n = sc . nextLong ( ) ; long k = sc . nextLong ( ) ; long x = ( long ) ( - 3 + ( Math . sqrt ( 9 + 8 * ( n + k ) ) ) ) / 2 ; System . out . println ( n - x ) ; }
(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: (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: (binary_expression left: (cast_expression type: (integral_type) value: (parenthesized_expression (binary_expression left: (unary_expression operand: (decimal_integer_literal)) right: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (decimal_integer_literal) right: (binary_expression left: (decimal_integer_literal) right: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))))))))))) right: (decimal_integer_literal)))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))))