An investigator interviewed 100 students to determine their preferences for the three drinks: milk (M), coffee(C) and tea (T). He reported the following : 10 students had all the three drinks M, C, T: 20 had M and C: 30 had C and T: 25 had M and T:12 had M only; 5 had C only: 8 had T only. Then how many did not take any of the three drinks