Smallest Substring - JAVA

import java.util.*;

public class Test {

    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {

        int n = sc.nextInt();
        String s = sc.next();
        int res = smallestSubstring(n, s);
        System.out.println(res);
    }

    public static int smallestSubstring(int n, String s) {
        char[] temp = s.toCharArray();

        // Check for length of 2
        for (int i = 0; i < n - 1; i++) {
            if (temp[i] == 'x' && temp[i + 1] == 'x')
                return 2;
        }

        // Check for length of 3
        for (int i = 0; i < n - 2; i++) {
            if (temp[i] == 'x' && temp[i + 2] == 'x')
                return 3;
        }

        // Check for length of 4
        for (int i = 0; i < n - 3; i++) {
            if (temp[i] == 'x' && temp[i + 3] == 'x' && temp[i + 1] != temp[i + 2])
                return 4;
        }

        // Check for length of 7
        for (int i = 0; i < n - 6; i++) {
            if (temp[i] == 'x' && temp[i + 3] == 'x' && temp[i + 6] == 'x') {
                int countY = 0, countZ = 0;
                for (int j = i + 1; j <= i + 5; j++) {
                    if (temp[j] == 'y')
                        countY++;
                    else if (temp[j] == 'z')
                        countZ++;
                }

                if (countY == 2 && countZ == 2)
                    return 7;
            }
        }
        return -1;
    }

}