How do I check if two words have a common char?

ex. : "word" and "letter" have common "r"

"word" and "email" haven't any common chars

This code is wrong because if two words have 2 common chars I get 4 in the result

```
int numberOfCommonChars = (from c1 in word1.ToCharArray()
                           from c2 in word2.ToCharArray()
                           where c1 == c2
                           select c1).Count();

```