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

### Instruction:
What is the sum of To Par, when Country is "United States", and when Year(s) Won is "1973"?

### Inputs:
table_name: table, columns: ['Player', 'Country', 'Year(s) won', 'Total', 'To par', 'Finish']

### Response:
SELECT SUM To par FROM table WHERE Country = united states AND Year(s) won = 1973