Half of the 30 students are girls, and 7 of them are not elementary school students. Find out how many female students are in elementary school.
30 2 [OP_DIV] 7 [OP_SUB]
var_a = 30
var_b = 2
var_c = var_a / var_b
var_d = 7
var_e = var_c - var_d
print(int(var_e))