平均年龄

import java.util.Scanner;/** * Created by h on 16-12-27. */public class Solution {    //w y x n    public static void main(String[] args) {        double w,y,x,n;        Scanner in = new Scanner(System.in);        while (in.hasNext()){            w = in.nextDouble();            y = in.nextDouble();            x = in.nextDouble();            n = in.nextDouble();            for(int i=1;i<=n;i++){                y = (1-x) * (y+1) + 21 * x;            }            System.out.println((int)Math.ceil(y));        }    }}