### Problem Statement

A common task for math students is to solve 'word math' questions, where each distinct letter represents a distinct digit.

Given a list of word math numbers to add, your task is to calculate the greatest possible sum of those numbers.

For example, given the expression:
```    TOP
+ CODER```
the maximum sum possible by substituting numbers is:
```    783
+ 98654
-------
99437```
with C = 9, D = 6, E = 5, O = 8, P = 3, R = 4 and T = 7.

### Definition

 Class: WordMath Method: maximumSum Parameters: String[] Returns: int Method signature: int maximumSum(String[] summands) (be sure your method is public)

### Notes

-Different letters must represent different digits, identical letters must represent identical digits.
-Not all digits in the result must appear in the summands.

### Constraints

-summands will contain between 1 and 10 elements, inclusive.
-Each element of summands will contain between 1 and 8 characters, inclusive.
-Each element of summands will contain only uppercase letters ('A'-'Z').
-summands will contain at most 10 distinct letters.

### Examples

0)

 `{"TOP", "CODER"}`
`Returns: 99437`
 The example given in the problem statement.
1)

 `{"AAA", "AAA"}`
`Returns: 1998`
 With only one letter, the maximum sum is obtained by setting A = 9.
2)

 `{"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}`
`Returns: 45`
 Each letter is used once, and there are 10 different letters, so however the digits are distributed this must add up to 0 + 1 + ... + 8 + 9 = 45
3)

 `{"AB", "BA"}`
`Returns: 187`
4)

 `{"READIEST","OPERATIC","TOPCODER","PREDICTS","RAPIDEST","ASTEROID","AIRSPEED"}`
`Returns: 563639653`

#### Problem url:

http://www.topcoder.com/stat?c=problem_statement&pm=6572

#### Problem stats url:

http://www.topcoder.com/tc?module=ProblemDetail&rd=10060&pm=6572

sql_lall

#### Testers:

PabloGilberto , brett1479 , Olexiy

Simple Math