The polynomial
f(x) = a_n x^n + a_{n - 1} x^{n - 1} + ... + a_2 x^2 + a_1 x + a_0
has integer coefficients, and its roots are distinct integers.
If a_n = 2 and $a_0 = 60$, what is the smallest possible value of |a_{n - 1}|?
