public static void main ( String [ ] args ) {
  Scanner scanner = new Scanner ( System . in ) ;
  int n = scanner . nextInt ( ) ;
  boolean [ ] [ ] graph = new boolean [ n ] [ n ] ;
  int [ ] sum = new int [ n ] ;
  int m = scanner . nextInt ( ) ;
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    int x = scanner . nextInt ( ) - 1 ;
    int y = scanner . nextInt ( ) - 1 ;
    graph [ x ] [ y ] = true ;
    graph [ y ] [ x ] = true ;
    sum [ x ] ++ ;
    sum [ y ] ++ ;
  }
  int min = 16000001 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    for ( int j = i + 1 ;
    j < n ;
    j ++ ) {
      if ( graph [ i ] [ j ] ) {
        for ( int k = j + 1 ;
        k < n ;
        k ++ ) {
          if ( graph [ j ] [ k ] && graph [ i ] [ k ] ) {
            min = Math . min ( sum [ i ] + sum [ j ] + sum [ k ] , min ) ;
          }
        }
      }
    }
  }
  if ( min == 16000001 ) min = 5 ;
  System . out . println ( min - 6 ) ;
}

public static void main ( String [ ] args ) { Scanner scanner = new Scanner ( System . in ) ; int n = scanner . nextInt ( ) ; boolean [ ] [ ] graph = new boolean [ n ] [ n ] ; int [ ] sum = new int [ n ] ; int m = scanner . nextInt ( ) ; for ( int i = 0 ; i < m ; i ++ ) { int x = scanner . nextInt ( ) - 1 ; int y = scanner . nextInt ( ) - 1 ; graph [ x ] [ y ] = true ; graph [ y ] [ x ] = true ; sum [ x ] ++ ; sum [ y ] ++ ; } int min = 16000001 ; for ( int i = 0 ; i < n ; i ++ ) { for ( int j = i + 1 ; j < n ; j ++ ) { if ( graph [ i ] [ j ] ) { for ( int k = j + 1 ; k < n ; k ++ ) { if ( graph [ j ] [ k ] && graph [ i ] [ k ] ) { min = Math . min ( sum [ i ] + sum [ j ] + sum [ k ] , min ) ; } } } } } if ( min == 16000001 ) min = 5 ; System . out . println ( min - 6 ) ; }
(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: (array_type element: (boolean_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (boolean_type) dimensions: (dimensions_expr (identifier)) dimensions: (dimensions_expr (identifier))))) (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))))) (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: (identifier)) update: (update_expression (identifier)) body: (block (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: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))) (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (true))) (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (true))) (expression_statement (update_expression (array_access array: (identifier) index: (identifier)))) (expression_statement (update_expression (array_access array: (identifier) index: (identifier)))))) (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: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal)))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier))) consequence: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal)))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (array_access array: (identifier) index: (identifier))) right: (array_access array: (identifier) index: (identifier))) (identifier))))))))))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (expression_statement (assignment_expression left: (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: (decimal_integer_literal)))))))