In Yoongi's class, there are 18 students who raise flower (a), 24 students who raise flower (b), and 7 students who raise both flower (a) and flower (b). If there is no student who does not raise any of flower (a) or flower (b), how many students are in Yoongi's class?
18 24 [OP_ADD] 7 [OP_SUB]
var_a = 18
var_b = 24
var_c = var_a + var_b
var_d = 7
var_e = var_c - var_d
print(int(var_e))