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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)


import java.io.*;
import java.util.StringTokenizer;

public class Main {
    public static void main(final String[] args) {
        final InputStream inputStream = System.in;
        final OutputStream outputStream = System.out;
        final InputReader in = new InputReader(inputStream);
        final PrintWriter out = new PrintWriter(outputStream);
        final Solution solver = new Solution();
        solver.solve(in, out);
        out.close();
    }

    static class Solution {
        void solve(final InputReader in, final PrintWriter out) {
            final int N = in.nextInt();
            final int K = in.nextInt();
            int currentValue = 1;
            for (int i = 0; i < N; i++) {
                currentValue = Math.min(currentValue * 2, currentValue + K);
            }
            out.println(currentValue);
        }

    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(final InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (final IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }
    }
}