1021. Remove Outermost Parentheses

class Solution {
public static String removeOuterParentheses(String S) {
	StringBuilder s = new StringBuilder();
    int opened = 0;
    for (char c : S.toCharArray()) {
        if (c == '('&& opened > 0 ) s.append(c);
        if (c == ')'&& opened > 1) s.append(c);
        if (c == '(') opened++;
        else opened--;
    }
    return s.toString();
}
}