The 30 students in Yejin's class have their own attendance numbers from 1 to 30. Among the students in Yejin's class, students wearing short sleeves today are students number 1, 3, 7, 10, 23, and 27, and students number 1, 9, 11, 20, and 23 are wearing short pants today, how many students were wearing short sleeves but not short pants today?
[OP_LIST_SOL] 1 3 7 10 23 27 [OP_LIST_EOL] [OP_LIST_SOL] 1 9 11 20 23 [OP_LIST_EOL] [OP_SET_DIFFERENCE] [OP_LIST_LEN]
var_a = 1
var_b = 3
var_c = 7
var_d = 10
var_e = 23
var_f = 27
list_a= []
if "/" in str(var_f):
    var_f = eval(str(var_f))
list_a.append(var_f)
if "/" in str(var_e):
    var_e = eval(str(var_e))
list_a.append(var_e)
if "/" in str(var_d):
    var_d = eval(str(var_d))
list_a.append(var_d)
if "/" in str(var_c):
    var_c = eval(str(var_c))
list_a.append(var_c)
if "/" in str(var_b):
    var_b = eval(str(var_b))
list_a.append(var_b)
if "/" in str(var_a):
    var_a = eval(str(var_a))
list_a.append(var_a)
list_a.reverse()
var_g = 1
var_h = 9
var_i = 11
var_j = 20
var_k = 23
list_b= []
if "/" in str(var_k):
    var_k = eval(str(var_k))
list_b.append(var_k)
if "/" in str(var_j):
    var_j = eval(str(var_j))
list_b.append(var_j)
if "/" in str(var_i):
    var_i = eval(str(var_i))
list_b.append(var_i)
if "/" in str(var_h):
    var_h = eval(str(var_h))
list_b.append(var_h)
if "/" in str(var_g):
    var_g = eval(str(var_g))
list_b.append(var_g)
list_b.reverse()
list_c = list(set(list_a) - set(list_b))
var_l = len(list_c)
print(int(var_l))