Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the sum of the weeks that games occured on october 21, 1974 and less than 50,623 fans attended?

### Inputs:
table_name: table, columns: ['Week', 'Date', 'Opponent', 'Result', 'Venue', 'Attendance']

### Response:
SELECT SUM Week FROM table WHERE Date = october 21, 1974 AND Attendance < 50,623