Seoyeon has 4 blocks with numbers on them. Find the sum of the numbers on two blocks that maximize the difference between the numbers written in the block. The blocks are numbered 1, 3, 7, and 9.
[OP_LIST_SOL] 1 3 7 9 [OP_LIST_EOL] 1 [OP_LIST_MAX] 1 [OP_LIST_MIN] [OP_ADD]
var_a = 1
var_b = 3
var_c = 7
var_d = 9
list_a= []
if "/" in str(var_d):
    var_d = eval(str(var_d))
list_a.append(var_d)
if "/" in str(var_c):
    var_c = eval(str(var_c))
list_a.append(var_c)
if "/" in str(var_b):
    var_b = eval(str(var_b))
list_a.append(var_b)
if "/" in str(var_a):
    var_a = eval(str(var_a))
list_a.append(var_a)
list_a.reverse()
var_e = 1
list_b=list_a.copy()
list_b.sort()
var_f = list_b[-var_e]
var_g = 1
list_c=list_a.copy()
list_c.sort()
var_h = list_c[var_g-1]
var_i = var_f + var_h
print(int(var_i))