Let n be the number of the step in the combo. Then, the point value for the nth step is :
S(n) = G(n) if the step is a Great step, and P(n) is the step is a Perfect step;
G(n) = 555 + 333n;
P(n) = 777 + 333n;
Therefore, the total point value for a combo of n steps is the summation of S(n) from 1 to n.