1.
If the function
f(x)={aπx+1,x5bxπ+3,x>5f(x) = \begin{cases} a\pi - x + 1, & x \le 5 \\ b|x - \pi| + 3, & x > 5 \end{cases}
is continuous at x=5x = 5, then the value of aba - b is: