package codeup100;

import java.util.Scanner;

public class c1091 {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

String[] nums = sc.nextLine().split(" ");

sc.close();

long a = Integer.parseInt(nums[0]); //시작값

int m = Integer.parseInt(nums[1]); //곱할값

int d = Integer.parseInt(nums[2]); //더할값

int n = Integer.parseInt(nums[3]); //몇번째인지 나타내는 숫자

//int에 넘치므로 long으로

//-50 50 -50 10 => -99649234693877550

for(int i=0; i<n-1; i++) {

a = (a*m+d);

}

System.out.println(a);

/* 연습

System.out.println(1*-2+1); //-1

System.out.println(-1*-2+1); //3

System.out.println(3*-2+1); //-5

System.out.println(-5*-2+1); //11

*/

}

}