PROGRAMMING:Even string (Cixi primary school, 2012)
The processing and operation of string is one of the eternal topics in program design, and it is also a very important basic skill. Are you familiar with strings?
Give you n (1 ≤ n ≤ 20) strings (1 ≤ string length ≤ 2000). All strings contain at most 14 capital letters from 'a' to 'n'. Select several strings to make the total number of each letter in the selected string even. Please program to calculate the maximum number of strings that can be selected?
###Input format:
Enter a total of N + 1 lines.
The first line is an integer n, which indicates how many strings there are.
In the next N lines, each line contains an unordered string containing at most 14 capital letters from 'a' to 'n' (regardless of invisible characters such as carriage return at the end of the line).
###Output format:
Output a total of 1 line, indicating the maximum number of strings that can be selected
###Input sample 1:
```in
two
A
AD
```
###Output sample 1:
```out
0
```
[explanation of example 1]
No matter how you choose the two strings in sample 1, you can't guarantee that each letter will add up to an even number.
###Input sample 2:
```in
three
AD
AD
AB
```
###Output sample 2:
```out
two
```
[example 2 explanation]
Select two "ad" strings in the input, so that there are two a and two D, both of which are even numbers.
###Input sample 3:
```in
five
AD
A
BA
B
D
```
###Output sample 3:
```out
four
```
[explanation of example 3]
Selecting "a", "Ba" and "B" can make the number of "a" and "B" even, but the number of selected strings is only 3, not the most. Select "ad", "Ba", "B" and "d" in the input, so that the total number of "a", "B" and "d" is even, and the total number of selected strings is 4, meeting the maximum number.
[data range agreement]
For 50% of the data, 1 ≤ n ≤ 15, 1 ≤ string length ≤ 200, and the string contains at most seven different letters from 'a' to 'g'.
For 100% data, 1 ≤ n ≤ 20, 1 ≤ string length ≤ 2000, and the string contains at most 14 different letters from 'a' to 'n'.
answer：If there is no answer, please comment
Give you n (1 ≤ n ≤ 20) strings (1 ≤ string length ≤ 2000). All strings contain at most 14 capital letters from 'a' to 'n'. Select several strings to make the total number of each letter in the selected string even. Please program to calculate the maximum number of strings that can be selected?
###Input format:
Enter a total of N + 1 lines.
The first line is an integer n, which indicates how many strings there are.
In the next N lines, each line contains an unordered string containing at most 14 capital letters from 'a' to 'n' (regardless of invisible characters such as carriage return at the end of the line).
###Output format:
Output a total of 1 line, indicating the maximum number of strings that can be selected
###Input sample 1:
```in
two
A
AD
```
###Output sample 1:
```out
0
```
[explanation of example 1]
No matter how you choose the two strings in sample 1, you can't guarantee that each letter will add up to an even number.
###Input sample 2:
```in
three
AD
AD
AB
```
###Output sample 2:
```out
two
```
[example 2 explanation]
Select two "ad" strings in the input, so that there are two a and two D, both of which are even numbers.
###Input sample 3:
```in
five
AD
A
BA
B
D
```
###Output sample 3:
```out
four
```
[explanation of example 3]
Selecting "a", "Ba" and "B" can make the number of "a" and "B" even, but the number of selected strings is only 3, not the most. Select "ad", "Ba", "B" and "d" in the input, so that the total number of "a", "B" and "d" is even, and the total number of selected strings is 4, meeting the maximum number.
[data range agreement]
For 50% of the data, 1 ≤ n ≤ 15, 1 ≤ string length ≤ 200, and the string contains at most seven different letters from 'a' to 'g'.
For 100% data, 1 ≤ n ≤ 20, 1 ≤ string length ≤ 2000, and the string contains at most 14 different letters from 'a' to 'n'.
answer：If there is no answer, please comment