new Thread(new Runnable(){ void run(){
long start=system.currenttime();
Double Money=A.showM();//200
long end=system.currenttime();
do{
end=system.currenttime();
}while(2000==end-start)
A.addM(100);
}}).start();
new Thread(new Runnable(){ void run(){
long start=system.currenttime();
Double Money=B.showM();//300
long end=system.currenttime();
do{
end=system.currenttime();
}while(2000==end-start)
A.getM(50);
}}).start();