21 liters (L) of ethanol was added to the flask for 6 minutes. The flask took 22 minutes and 30 seconds to be filled, with 0.3 liters (L) of ethanol draining out per minute. Find how many liters (L) the volume of the first flask was.
21 6 [OP_DIV] 0.3 [OP_SUB] 22 30 60 [OP_DIV] [OP_ADD] [OP_MUL]
var_a = 21
var_b = 6
var_c = var_a / var_b
var_d = 0.3
var_e = var_c - var_d
var_f = 22
var_g = 30
var_h = 60
var_i = var_g / var_h
var_j = var_f + var_i
var_k = var_e * var_j
print(int(var_k))