There is a volleyball, soccerball, basketball, and baseball. If Youngbin buys two different balls, how many ways can he choose the ball?
[OP_LIST_SOL] volleyball soccerball basketball baseball [OP_LIST_EOL] [OP_LIST_LEN] 2 [OP_COMB]
var_a = 'volleyball'
var_b = 'soccerball'
var_c = 'basketball'
var_d = 'baseball'
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 = len(list_a)
var_f = 2
var_g = 1
var_e = int(var_e)
var_f = int(var_f)
for i, elem in enumerate(range(var_f)):
    var_g = var_g * (var_e-i)
for i, elem in enumerate(range(var_f)):
    var_g = var_g / (i+1)
print(int(var_g))