Thirty students are in line to catch the bus. If there are 20 students in front of Yoongi, how many students will get on the bus later than Yoongi?
30 20 [OP_SUB] 1 [OP_SUB]
var_a = 30
var_b = 20
var_c = var_a - var_b
var_d = 1
var_e = var_c - var_d
print(int(var_e))