a=[8,12,16,18,20,24,12,18,24,27,30,36,20,30,40,45,50,60,28,42,56,63,70,84,44,66,88,99,110,132,52,78,104,117,130,156]
k=gets.to_i
p a.inject(0){|s,e|e==k ? s+1 : s}/36.0