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 ( ) ;
  HashMap < String , Integer > namemap = new HashMap < String , Integer > ( ) ;
  HashMap < String , Integer > kitmap = new HashMap < String , Integer > ( ) ;
  for ( int i = 0 ;
  i < N ;
  i ++ ) {
    String s = String . valueOf ( name . charAt ( i ) ) ;
    if ( namemap . containsKey ( s ) ) {
      namemap . put ( s , namemap . get ( s ) + 1 ) ;
    }
    else {
      namemap . put ( s , 1 ) ;
    }
  }
  for ( int i = 0 ;
  i < M ;
  i ++ ) {
    String s = String . valueOf ( kit . charAt ( i ) ) ;
    if ( kitmap . containsKey ( s ) ) {
      kitmap . put ( s , kitmap . get ( s ) + 1 ) ;
    }
    else {
      kitmap . put ( s , 1 ) ;
    }
  }
  int ans = 0 ;
  for ( String s : namemap . keySet ( ) ) {
    int num1 = namemap . get ( s ) ;
    int num2 = 0 ;
    if ( kitmap . containsKey ( s ) ) num2 = kitmap . get ( s ) ;
    if ( num2 == 0 ) {
      ans = - 1 ;
      break ;
    }
    else {
      ans = Math . max ( ans , ( num1 + num2 - 1 ) / num2 ) ;
    }
  }
  System . out . println ( ans ) ;
}

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 ( ) ; HashMap < String , Integer > namemap = new HashMap < String , Integer > ( ) ; HashMap < String , Integer > kitmap = new HashMap < String , Integer > ( ) ; for ( int i = 0 ; i < N ; i ++ ) { String s = String . valueOf ( name . charAt ( i ) ) ; if ( namemap . containsKey ( s ) ) { namemap . put ( s , namemap . get ( s ) + 1 ) ; } else { namemap . put ( s , 1 ) ; } } for ( int i = 0 ; i < M ; i ++ ) { String s = String . valueOf ( kit . charAt ( i ) ) ; if ( kitmap . containsKey ( s ) ) { kitmap . put ( s , kitmap . get ( s ) + 1 ) ; } else { kitmap . put ( s , 1 ) ; } } int ans = 0 ; for ( String s : namemap . keySet ( ) ) { int num1 = namemap . get ( s ) ; int num2 = 0 ; if ( kitmap . containsKey ( s ) ) num2 = kitmap . get ( s ) ; if ( num2 == 0 ) { ans = - 1 ; break ; } else { ans = Math . max ( ans , ( num1 + num2 - 1 ) / num2 ) ; } } 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 (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: (generic_type (type_identifier) (type_arguments (type_identifier) (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments (type_identifier) (type_identifier))) arguments: (argument_list)))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier) (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments (type_identifier) (type_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: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) consequence: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (decimal_integer_literal)))))) alternative: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (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: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) consequence: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (decimal_integer_literal)))))) alternative: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (decimal_integer_literal)))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (enhanced_for_statement type: (type_identifier) name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) 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 (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (unary_expression operand: (decimal_integer_literal)))) (break_statement)) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) right: (identifier)))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))