BALKAN 1992 Problem 1

For all positive integers $m,n$ define $f(m,n) = m^{3^{4n}+6} - m^{3^{4n}+4} - m^5 + m^3$ . Find all numbers $n$ with the property that $f(m, n)$ is divisible by 1992 for every $m$ .

Bulgaria