问如何在数学任务中使用我的输入

EN

package atm;

import java.util.Scanner;

public class ATM {

    public static void main(String[] args) {

    int a, b, c, d;
    a = 20;
    b = 10;
    c = 5;
    d = 1;

    Scanner user_input = new Scanner(System.in);

    String withdraw;
    System.out.print("Put an amount of \u0024 to withdraw: ");
    withdraw = user_input.next ();

    System.out.println(withdraw / a);

    System.out.println("Amount is \u0024 " + withdraw);

    user_input.close();  
    }
}