Leetcode - Goal Parser Interpretation

class Solution {
public:
    string interpret(string command) {
        string answer = "";
        for (int i = 0 ; i < command.size() ; i++){
            if (command[i] == '(' && command[i+1] == ')'){
                answer += 'o';
            }
            else if (command[i] == '(' && command[i+1] == 'a' && command[i+2] == 'l' && 
                    command[i+3] == ')'){
                answer += "al";
            }
            else if (command[i] == 'G')
                answer += 'G';
        }
        return answer;
    }
};