There are 40 ducks and 30 rabbits on the farm. Also, the number of hens is 20 more than ducks, and the number of roosters is 10 fewer than rabbits. How many chickens are there in the farm totally?
40 20 [OP_ADD] 30 10 [OP_SUB] [OP_ADD]
var_a = 40
var_b = 20
var_c = var_a + var_b
var_d = 30
var_e = 10
var_f = var_d - var_e
var_g = var_c + var_f
print(int(var_g))