There are currently 63 people on the train. 78 people were on the train when it first departed, and 27 people got off after that. How many extra people got on the train?
63 27 [OP_ADD] 78 [OP_SUB]
var_a = 63
var_b = 27
var_c = var_a + var_b
var_d = 78
var_e = var_c - var_d
print(int(var_e))