public static int migratoryBirds(List<Integer> arr) {
        int[] freq = new int[5];
        int n = arr.size();
        int max = 0;

        for (int i: arr) {
            freq[i - 1]++;
            if (freq[i - 1] > max)
            max = freq[i - 1];
        }
        
        for (int i = 0; i < 5; i++) {
            if (freq[i] == max)
            return i + 1;
        }
        
        return -1;
    }