An investigator interviewed 100 students to determine the performance of three drinks: milk, coffee and tea; 20 students take milk and coffee; and tea. The investigator reported that 10 students take all three drinks milk, coffee and tea; 20 students take milk and coffee; 25 students take milk and ta; 20 students take coffee and; 12 students take milk only; 5 students take coffee only and 8 students take tea only. Then the number of student who did not take any of three drinks is