/**

* BigInteger exercise.

*/

import java.math.BigInteger;

public class Pow {

public static void main(String[] args) {

System.out.println(pow(27, 13));

}

/**

* Integer exponentiation.

*/

public static BigInteger pow(int x, int n) {

BigInteger one = BigInteger.valueOf(1);

if (n == 0) return one;

// find x to the n/2 recursively

BigInteger bigX = BigInteger.valueOf(x);

BigInteger t = pow(x, n / 2);

// if n is even, the result is t squared

// if n is odd, the result is t squared times x

// if (n % 2 == 0) {

// return t * t;

// } else {

// return t * t * x;

// }

if (n % 2 == 0) {

return t.multiply(t);

} else {

return t.multiply(t.multiply(bigX));

}

}

}