class Exp {

    /* Computes a^n fast. */
    static long exp(int a, int n) {
        if (n == 0)
            return 1; // base case
        if (n % 2 == 1) // n is odd
            return exp(a, n-1) * a;
        else // n is even
            return exp(a*a, n/2);
    }

    public static void main(String[] args) {
        int a = 3;
        int n = 27164512;
        System.out.printf("exp(%d, %d) = %d%n", a, n, exp(a, n));
    }
}