The barrel has contained 4 fish (a) and 3 fish (b). I bought some more fish today and put them in the barrel, so there are 10 fish in total. How many more fish did I put in today?
10 4 3 [OP_ADD] [OP_SUB]
var_a = 10
var_b = 4
var_c = 3
var_d = var_b + var_c
var_e = var_a - var_d
print(int(var_e))