package CSP.A202212.A1; /**
 * @Projectname: LeetCode
 * @Filename: CSP.A202212.A1.CSP.A202209.A1.CSP.A202203.A1.CSP.A201312.A1.CSP.A202305.A2.CSP.A202303.A2.CSP.A201612.A2.CSP.A202212.A2.CSP.A202209.A2.CSP.A202206.A2.CSP.A202203.A2.CSP.A202305.A3.CSP.A202303.A3.CSP.A202212.A3.CSP.temp.A1.CSP.temp.A2.CSP.temp.A3.CSP.temp.A4.CSP.temp.A5.Main
 * @Author: 杨逸
 * @Data:2023/8/16 10:24
 * @Description: 现值计算-第一题
 */
import java.util.Scanner;
public class Main {
    private static int n;
    private static double rate;
    public static void main(String[] args) {
        //数据输入
        Scanner scanner = new Scanner(System.in);
        n = scanner.nextInt();
        rate = scanner.nextDouble();

        //使用一个数组保存未来的收支情况
        double[] data = new double[n+1];
        for (int i = 0; i < data.length; i++) {
            data[i] = scanner.nextDouble();
        }

        double result = 0;
        //计算收益
        for (int i = 0; i < data.length; i++) {
            result += Math.pow((1.0+rate),-i)*data[i];
        }
        //输出结果
        System.out.println(result);
    }

}