class Summation {
  public static void main(String[] arg) {
    System.out.println(sumInts(3,7)); 
    System.out.println(sumInts(3,3));
    System.out.println(sumInts(7,3));
    System.out.println(sumEvenSquares(8));
    System.out.println(sumEvenSquares(9));
    System.out.println(sumEvenSquares(16));
  }
  private static int doSumInts(int x,int y) {
    int sum;

    if(x == y) {
      sum = x;
    }
    else {
      sum = x + doSumInts(x+1, y);
    }
    return sum;
  }
  public static int sumInts(int x, int y) {
    if(x > y) {
      int temp = x;
      x = y;
      y = temp;
    }
    return doSumInts(x,y);
  }
  public static int sumEvenSquares(int n) {
    int result;

    if(n <= 1) {
      result = 0;
    }
    else if((n % 2) == 0) {
      result = n * n + sumEvenSquares(n - 2);
    }
    else {
      result = sumEvenSquares(n - 1);
    }
    return result;
  }
}