Hi anh Thanh, > Co' phai? la`: " dia. u`,tho^ng chiu' U` bach. thu? U` Chi, kinh'tu(' Chi > hai to^m tai. ma? co' thie^n khai" khO^ng ? Lam`on chi? giup'to^i nhe'. It depends on how you give each kind of "u'" how many "di.ch".For us,if you "u` tha^.p tha`nh",you double all the "di.ch" you have. Cheers, --Tua^'n.