import java.util.concurrent.locks.*;

public class BankAccount{
    double balance = 0.0;
    Lock mutex = new ReentrantLock();

    public void deposit(double amount){
	mutex.lock();
        try{
          balance = balance+amount;
	}
	finally{
	    mutex.unlock();
	}
    }
    public void withdraw(double amount){
	mutex.lock();
        try{
          balance = balance-amount;
	}
	finally{
	    mutex.unlock();
	}
    }
    public double getBalance(){
     	mutex.lock();
        try{
	    return balance;
	}
	finally{
	    mutex.unlock();
	}
    }
}