// lifted from DS&A book (Preiss)

public class geosum0 {

    public static void main(String[] args) {
	
	int x = Integer.parseInt(args[0]);
	int n = Integer.parseInt(args[1]);
	
	System.out.println("Sum1: "+geosum1(x,n));
	System.out.println("Sum2: "+geosum2(x,n));
    }
    
    public static int geosum1(int x, int n) {
	int sum=0;
	for (int i=0;i<=n;i++) {
	    int prod=1;
	    for (int j=0;j<i;j++)
		prod *= x;
	    sum += prod;
	}
	return sum;
    }

    public static int geosum2(int x, int n) {
	int sum=0;
	for(int i=0;i<=n; i++)
	    sum = sum*x + 1;
	return sum;
    }
}
/*
> java geosum0 2 4
  Sum1: 31
  Sum2: 31

  sum(2^i,i=0..4) 
      = 2^0 + 2^1 + 2^2 + 2^3 + 2^4
      =  1 + (2)(1 + 2^1 + 2^2 + 2^3)
         ...
      =  1 + (2)(1 + (2)(1 + (2)(1 + (2)(1))))
      =  31
*/