某程序段如下：Y = 50;Z = 80; X = 30;X = Z + Y; If Y > Z　{ X = X - Y; }Else { X= X - Z; }X = X + Y; If X > Z { X = Y; } X = X - Z; If X>Y{ X = X - Y; }该程序执行完成后，X、Y、Z的值分别为_____。