When 13 is divided by A, the quotient is 4, the remainder is B. A and B are both natural numbers. Find the largest possible value of A.
13 1 [OP_SUB] 4 [OP_FDIV]
var_a = 13
var_b = 1
var_c = var_a - var_b
var_d = 4
var_e = var_c // var_d
print(int(var_e))