public static final BigInteger _3=BigInteger.valueOf(3);

public static BigInteger cbrt(BigInteger num)
{
 BigInteger root=BigInteger.ZERO.setBit(num.bitLength()/3),temp;
 do {
  temp=root;
  root=temp.add(temp).add(num.divide(temp.multiply(temp))).divide(_3);
 } while(!root.equals(temp));
}

public static final BigDecimal _3=BigDecimal.valueOf(3);
public static final int UP=BigDecimal.ROUND_HALF_UP;

public static BigInteger cbrt(BigInteger num)
{
 BigDecimal numD=new BigDecimal(num),temp;
 BigInteger root=BigInteger.ZERO.setBit(num.bitLength()/3);
 do {
  temp=new BigDecimal(root);
  root=temp.add(temp).add(numD.divide(temp.multiply(temp),UP)).divide(_3,UP).toBigInteger();
 } while(!root=temp.toBigInteger());
}

public static final BigInteger _3=BigInteger.valueOf(3);

public static BigInteger cbrt(BigInteger num)
{
 BigInteger root=BigInteger.ZERO.setBit(num.bitLength()/3),temp;
 do {
  temp=root;
  root=temp.add(temp).add(num.divide(temp.multiply(temp))).divide(_3);
 } while(root.compareTo(temp)>0);
}

public static final BigInteger _3=BigInteger.valueOf(3);

public static BigInteger cbrt(BigInteger n)
{
 BigInteger root=BigInteger.ZERO.setBit(n.bitLength()/3),t1,t2,t3;
 t1=t2=t3=BigInteger.ZERO;
 do {
  t3=t2;t2=t1;t1=root;
  root=t1.add(t1).add(n.divide(t1.multiply(t1))).divide(_3);
 } while(!root.equals(t1.add(t2).add(t3).divide(_3)));
 return root;
}

private static final BigInteger THREE = BigInteger.valueOf(3);

private static BigInteger cubeRoot(BigInteger n) {
    // Using Newton's method, we approximate the cube root
    // of n by the sequence:
    // x_{i + 1} = frac{1}{3} left( frac{n}{x_i^2} + 2 x_i right).
    // See http://en.wikipedia.org/wiki/Cube_root#Numerical_methods.
    //
    // Implementation based on Section 1.7.1 of
    // "A Course in Computational Algebraic Number Theory"
    // by Henri Cohen.
    BigInteger x = BigInteger.ZERO.setBit(n.bitLength() / 3 + 1);
    BigInteger y = BigInteger.ZERO;

    while (true) {
        y = x.shiftLeft(1).add(n.divide(x.multiply(x))).divide(THREE);
        if (y.compareTo(x) >= 0) {
            break;
        }

        x = y;
    }

    return x;
}

for (int i = 1; i < Integer.MAX_VALUE; i++) {
    // Report progress.
    if (i % 1000000 == 0) {
        System.out.printf("%d%n", i);
    }

    BigInteger n = BigInteger.valueOf(i);
    BigInteger m = cubeRoot(n);

    BigInteger lower = m.pow(3);
    BigInteger upper = m.add(BigInteger.ONE).pow(3);

    if (lower.compareTo(n) <= 0 && n.compareTo(upper) < 0) {
        continue;
    }

    System.err.printf("Error for input %s: Got %s%n", n, m);
    System.err.printf("Expected m^3 <= %s < (m + 1)^3%n", n);
    System.err.printf("But m^3 = %s, (m + 1)^3 = %s%n", lower, upper);
}