Yoongi can choose 3 out of 10 classes for after-school classes. How many ways can Yoongi take classes?
10 3 [OP_COMB]
var_a = 10
var_b = 3
var_c = 1
var_a = int(var_a)
var_b = int(var_b)
for i, elem in enumerate(range(var_b)):
    var_c = var_c * (var_a-i)
for i, elem in enumerate(range(var_b)):
    var_c = var_c / (i+1)
print(int(var_c))