sample space = {s1, s2, s3, s4, m1, m2, m3, m4, l1, l2, l3, l4, s1234, s123, s124, s12, s13, s14, s23, s24, s34, m1234, m123, m12, m13, m14, m23, m24, m34, l1234, l123, l12, l13, l14, l23, l24, l34}
total with one topping = 12
s - small
m - medium
l - large
1 - pepperoni
2 - sausage
3 - green pepper
4 - mushroom
