I'm trying to calculate the number of possible password combinations when my password consists of 6 characters that can be
- uppercase letters
- lowercase letters
I know that if there are no requirements, the amount of possible combinations equals $(26+26+10)^6$, but I am trying to satisfy for the requirement that there must be at least 1 uppercase character, at least 1 lowercase character, and at least 1 digit.
My strategy is to consider that my password can be of the form $(U,L,D,\star,\star,\star)$, with for $U$ and $L$ $26$ possibilities, for $D$ $10$ possibilities, and for $\star$ $62$ possibilities. Then, I only need to correct for their order, but I do not know how to do this.
Any possible steps to take would be very much appreciated.