```
public class Solution {
public int titleToNumber(String s) {
int result = 0;
s= s.toUpperCase();
int length = s.length();
if(length == 1){
return letterIndex(s.charAt(0));
}
int pow = length-1;
for(int i =0; i< length-1; i++){
int num = letterIndex(s.charAt(i));
result += num*Math.pow(26, pow);
pow--;
}
return result + letterIndex(s.charAt(length-1));
}
public int letterIndex(char c){
return c-64;
}
```

}