Problem B
Double Password
A computer at ICPC headquarters is protected by a four-digit password—in order to log in, you normally need to guess the four digits exactly. However, the programmer who implemented the password check left a backdoor in the computer—there is a second four-digit password. If the programmer enters a four-digit sequence, and for each digit position the digit entered matches at least one of the two passwords in that same position, then that four-digit sequence will log the programmer into the computer.
Given the two passwords, count the number of distinct four-digit sequences that can be entered to log into the computer.
Input
The input consists of exactly two lines. Each of the two lines contains a string $s$ ($|s|~ =~ 4$, $s~ \in ~ \{ \texttt{0-9}\} ^*$). These are the two passwords.
Output
Output a single integer, which is the number of distinct four-digit sequences that will log the programmer into the system.
| Sample Input 1 | Sample Output 1 |
|---|---|
1111 1234 |
8 |
| Sample Input 2 | Sample Output 2 |
|---|---|
2718 2718 |
1 |
