socac tap con cua A = C1/6 +C2/6 + C3/6 +....+C6/6 =2^6
tong phan tu MAX cua B va C la 10+11+12+13+14=60(vi toi da 5 phan tu)
64 tap con nhan nhieu nhat 61 gia tri ---> ton tai 2 thang bang nhau
(neu chung co chung phan tu nao thi chi viec loai no ra )