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

### Instruction:
How many weeks have an Opponent of at san francisco 49ers, and an Attendance smaller than 34,354?

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

### Response:
SELECT COUNT Week FROM table WHERE Opponent = at san francisco 49ers AND Attendance < 34,354