class Solution {
public char findTheDifference(String s, String t) {
int [] result = new int[26];
for (int i =0;i<s.length();i++){
result[s.charAt(i)-'a']+=1;
}
for (int i=0;i<t.length();i++){
result[t.charAt(i)-'a']-=1;
if (result[t.charAt(i)-'a']<0) return t.charAt(i);
}
return ' ';
}}
