Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_19 (frequency_mhz VARCHAR, call_sign VARCHAR, erp_w VARCHAR)
### Question:
What is the total frequency mhz of the kgrj call sign, which has an erp w greater than 21,500?
### Answer:
SELECT COUNT(frequency_mhz) FROM table_name_19 WHERE call_sign = "kgrj" AND erp_w > 21 OFFSET 500