public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int N = sc . nextInt ( ) ;
  int M = sc . nextInt ( ) ;
  String name = sc . next ( ) ;
  String kit = sc . next ( ) ;
  char n [ ] = new char [ 26 ] ;
  char m [ ] = new char [ 26 ] ;
  for ( int i = 0 ;
  i < N ;
  i ++ ) {
    char nc = name . charAt ( i ) ;
    n [ nc - 'A' ] ++ ;
  }
  for ( int i = 0 ;
  i < M ;
  i ++ ) {
    char nk = kit . charAt ( i ) ;
    m [ nk - 'A' ] ++ ;
  }
  int an = Integer . MIN_VALUE ;
  for ( int i = 0 ;
  i < N ;
  i ++ ) {
    char target = name . charAt ( i ) ;
    int count = 0 ;
    if ( m [ target - 'A' ] == 0 ) {
      System . out . println ( - 1 ) ;
      return ;
    }
    if ( n [ target - 'A' ] % m [ target - 'A' ] == 0 ) {
      count = n [ target - 'A' ] / m [ target - 'A' ] ;
    }
    else {
      count = n [ target - 'A' ] / m [ target - 'A' ] + 1 ;
    }
    an = Math . max ( an , count ) ;
  }
  System . out . println ( an ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int N = sc . nextInt ( ) ; int M = sc . nextInt ( ) ; String name = sc . next ( ) ; String kit = sc . next ( ) ; char n [ ] = new char [ 26 ] ; char m [ ] = new char [ 26 ] ; for ( int i = 0 ; i < N ; i ++ ) { char nc = name . charAt ( i ) ; n [ nc - ' A ' ] ++ ; } for ( int i = 0 ; i < M ; i ++ ) { char nk = kit . charAt ( i ) ; m [ nk - ' A ' ] ++ ; } int an = Integer . MIN_VALUE ; for ( int i = 0 ; i < N ; i ++ ) { char target = name . charAt ( i ) ; int count = 0 ; if ( m [ target - ' A ' ] == 0 ) { System . out . println ( - 1 ) ; return ; } if ( n [ target - ' A ' ] % m [ target - ' A ' ] == 0 ) { count = n [ target - ' A ' ] / m [ target - ' A ' ] ; } else { count = n [ target - ' A ' ] / m [ target - ' A ' ] + 1 ; } an = Math . max ( an , count ) ; } System . out . println ( an ) ; }
(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: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (type_identifier) 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) dimensions: (dimensions) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (decimal_integer_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) dimensions: (dimensions) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (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 (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (expression_statement (update_expression (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_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 (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (expression_statement (update_expression (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (field_access object: (identifier) field: (identifier)))) (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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal))) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (unary_expression operand: (decimal_integer_literal))))) (return_statement))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal))) right: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal)))) right: (decimal_integer_literal))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal))) right: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal))))))) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal))) right: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (character_literal)))) right: (decimal_integer_literal)))))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))