Find the present value of the following semiannual cash flow stream if the interest rate is 4.4% compounded weekly. (Parenthesis denotes a negative value) The following cash flows start at the end of period 1:

($500) $3200 $4400 $200 ($110) $161 $509

It goes from period 1 to period 7. I am most confused about what to put as the exponent when setting up the equation