Final Value of Variable After Performing Operations

class Solution {
    public int finalValueAfterOperations(String[] operations) {
        int res = 0;
        String a = "++X";
        String b = "X++";
        for(String o : operations)
        {
            if(o.equals(a) || o.equals(b))
                res++;
            else
                res--;
        }
        return res;
    }
}