20 rabbits are lined up. How many rabbits are there between the 13th and 19th rabbits from the left?
19 13 [OP_SUB] 1 [OP_SUB]
var_a = 19
var_b = 13
var_c = var_a - var_b
var_d = 1
var_e = var_c - var_d
print(int(var_e))