There are 56 oak trees. There are 18 fewer ginkgo trees than pear trees, and 12 more ginkgo trees than maple trees. How many maple trees are there in all?
56 18 [OP_SUB] 12 [OP_SUB]
var_a = 56
var_b = 18
var_c = var_a - var_b
var_d = 12
var_e = var_c - var_d
print(int(var_e))