public static void main ( String args [ ] ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int k = sc . nextInt ( ) ;
  sc . nextLine ( ) ;
  String str = sc . nextLine ( ) ;
  int a = str . indexOf ( 'G' ) ;
  int b = str . indexOf ( 'T' ) ;
  if ( a < b ) {
    for ( int i = a ;
    i <= b ;
    i = i + k ) {
      if ( str . charAt ( i ) == '#' ) {
        System . out . println ( "NO" ) ;
        System . exit ( 0 ) ;
      }
      else if ( str . charAt ( i ) == 'T' ) {
        System . out . println ( "YES" ) ;
        System . exit ( 0 ) ;
      }
    }
    System . out . println ( "NO" ) ;
  }
  else {
    for ( int i = a ;
    i >= b ;
    i = i - k ) {
      if ( str . charAt ( i ) == '#' ) {
        System . out . println ( "NO" ) ;
        System . exit ( 0 ) ;
      }
      else if ( str . charAt ( i ) == 'T' ) {
        System . out . println ( "YES" ) ;
        System . exit ( 0 ) ;
      }
    }
    System . out . println ( "NO" ) ;
  }
}

public static void main ( String args [ ] ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int k = sc . nextInt ( ) ; sc . nextLine ( ) ; String str = sc . nextLine ( ) ; int a = str . indexOf ( ' G ' ) ; int b = str . indexOf ( ' T ' ) ; if ( a < b ) { for ( int i = a ; i <= b ; i = i + k ) { if ( str . charAt ( i ) == ' # ' ) { System . out . println ( " NO " ) ; System . exit ( 0 ) ; } else if ( str . charAt ( i ) == ' T ' ) { System . out . println ( " YES " ) ; System . exit ( 0 ) ; } } System . out . println ( " NO " ) ; } else { for ( int i = a ; i >= b ; i = i - k ) { if ( str . charAt ( i ) == ' # ' ) { System . out . println ( " NO " ) ; System . exit ( 0 ) ; } else if ( str . charAt ( i ) == ' T ' ) { System . out . println ( " YES " ) ; System . exit ( 0 ) ; } } System . out . println ( " NO " ) ; } }
(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 (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)))) (expression_statement (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) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (character_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (character_literal))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (identifier))) condition: (binary_expression left: (identifier) right: (identifier)) update: (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (identifier))) condition: (binary_expression left: (identifier) right: (identifier)) update: (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))))