Problem:
Score : 200 points

Problem Statement

Square1001 has seen an electric bulletin board displaying the integer 1.
He can perform the following operations A and B to change this value:

Operation A: The displayed value is doubled.

Operation B: The displayed value increases by K.

Square1001 needs to perform these operations N times in total.
Find the minimum possible value displayed in the board after N operations.

Constraints

1 \leq N, K \leq 10

All input values are integers.

Input

Input is given from Standard Input in the following format:

N
K

Output

Print the minimum possible value displayed in the board after N operations.

Sample Input 1

4
3

Sample Output 1

10

The value will be minimized when the operations are performed in the following order: A, A, B, B.

In this case, the value will change as follows: 1 → 2 → 4 → 7 → 10.

Sample Input 2

10
10

Sample Output 2

76

The value will be minimized when the operations are performed in the following order: A, A, A, A, B, B, B, B, B, B.

In this case, the value will change as follows: 1 → 2 → 4 → 8 → 16 → 26 → 36 → 46 → 56 → 66 → 76.

By the way, this contest is AtCoder Beginner Contest 076.

Solution in Go (1.6) (judge verdict: Wrong Answer)

// Package main provides
//
// File:  b.go
// Author: ymiyamoto
//
// Created on Mon Jan  7 00:09:03 2019
//
package main

import "fmt"

func main() {
	var N, K int
	fmt.Scan(&N, &K)

	ans := 0
	for i := 0; i < (1 << 10); i++ {
		n := N
		for j := uint8(0); j < 10; j++ {
			if i&(1<<j) != 0 {
				n *= 2
			} else {
				n += K
			}
		}
		if ans < n {
			ans = n
		}
	}

	fmt.Println(ans)
}