```
public class Solution {
public char findTheDifference(String s, String t) {
int lengthS = s.length(); //Can be zero
int lengthT = t.length(); //Should be lengthS + 1
if(lengthS == 0) return t.charAt(0);
int sumS = findLetter(s, lengthS); //Smaller
int sumT = findLetter(t, lengthT); //Larger
int addedLetterASCII = sumT-sumS;
return (char) addedLetterASCII;
}
private int findLetter(String a, int length){
int sum = 0;
for(int pos = 0; pos < length; pos++){
sum += (int) a.charAt(pos);
}
return sum;
}
}
```