python3

javascript

java

 Letter Tile Possibilities

You are given a String `tiles`, where each tile has one letter `tiles[i]` printed on it.

Return the number of possible non-empty sequences of letters you can make using the letters printed on those tiles.

### Input Format:
First parameter: String `tiles`
 
### Output Format:
Return the number.

### Example 1:
```
Input:
AAB
Output:
8
Explanation: The possible sequences are "A", "B", "AA", "AB", "BA", "AAB", "ABA", "BAA".
```
### Example 2:
```
Input:
AAABBC
Output: 
188
```

### Constraints:

+ 1 <= tiles.length <= 7
+ tiles consists of uppercase English letters.
+ Expected Time Complexity: O(n!)
+ Expected Space Complexity: O(n!)

static int solve(String tiles){
//CODE HERE 
}