A class of 60 students were asked whether they belonged to the music club(M), debating club (D) or writers club (W). 10 students belong to M only , 11 belonged to W only and 14 belonged to D only. 8 students belonged to W and D but not M. 11 belonged to both D and M. Those who belonged to all the three the three clubs were one more than those who belonged to M and W only. 2 students belonged to none of the clubs .find the number of students who belong to all the three clubs.​