The hypothesis test

$\displaystyle \qquad \begin{array}{c} H_0: \mu = 20 \\ H_1: \mu \not= 20\\ \end{array}$
is to be carried out. A random sample is selected, and yields $\bar{x} = 24$ and s = 13. If the value of the t statistic is $t = 1.30542790372901$, what is the sample size? (If rounding is required, round to the nearest integer.)

Sample Size =