 We need to subtract a number from 66 and add 21, but we accidently added this number to 66 and 93 came out. How much do you get when you calculate correctly? 
66 93 66 [OP_SUB] [OP_SUB] 21 [OP_ADD]
var_a = 66
var_b = 93
var_c = 66
var_d = var_b - var_c
var_e = var_a - var_d
var_f = 21
var_g = var_e + var_f
print(int(var_g))