写了一个小程序，我觉应该是同步的，但结果不正确。程序是模拟银行账户的流水

public class Account {
    
    private int money = 60000;

    public int getMoney() {
        return money;
    }
    
    public void setMoney(int money) {
        this.money = money;
    }
    
    
}

public class Save implements Runnable{
    
    private Account account;
    
    public Save(Account account) {
        this.account=account;
    }
    @Override
    public void run() {
        
            for(int i=0;i<50000;i++){
                synchronized (account) {  //连续执行一定放入同步快中
                    account.setMoney(account.getMoney()+1);
//                    System.out.println("向账户存了1元，账户余额"+account.getMoney()+"元");
                }


            }

        
    }
}

public class Take implements Runnable{
    
    private Account account;
    
    public Take(Account account) {
        this.account=account;
    }
    @Override
    public void run() {
        
            for(int i=0;i<50000;i++){
                synchronized (account) {
                    if(account.getMoney() > 0){
                        account.setMoney(account.getMoney()-1);
//                        System.out.println("向账户取了1元，账户余额"+account.getMoney()+"元");
                    }else{
//                        System.out.println("账户余额不足");
                    }

                }

            }
        
        
    }
}

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Account account = new Account();
        
        Save save = new Save(account);
        Take take = new Take(account);
        
        Thread thread1 = new Thread(save);
        Thread thread2 = new Thread(take);
        
        System.out.println("账户余额为"+account.getMoney());
        System.out.println("开始");
        
        thread1.start();
        thread2.start();
        System.out.println("最后账户余额为："+account.getMoney());
    }
    
}

存钱和取钱的钱数是一样的，所以总数应该还是60000，但结果不是这个数。是不是我Main线程先运行结束了？所以显示出来的“最后账户余额”不正确。