Untitled

public class CountPairs {
    public static void main(String[] args) {
        System.out.println(countPairs(3));

    }

    public static int countPairs(int n) {
        return countPairs(n, 0, 0, "");
    }

    private static int countPairs(int n, int open, int close, String print) {
        if (open == n && close == n) {
            System.out.println(print);
            return 1;
        }
        if (open == 0 || open == close && open < n) {
            return countPairs(n, open + 1, close, print + "(");
        }
        if (open == n) {
            return countPairs(n, open, close + 1, print + ")");
        } else {
            return countPairs(n, open + 1, close, print + "(") + countPairs(n, open, close + 1, print + ")");
        }

    }
}