class Solution {
    public List<Integer> intersection(int[][] nums) {
        Map<Integer, Integer> cnt = new HashMap<>();
        List<Integer> ans = new ArrayList<>();
        for (var arr : nums) {
            for (int x : arr) {
                if (cnt.merge(x, 1, Integer::sum) == nums.length) {
                    ans.add(x);
                }
            }
        }
        Collections.sort(ans);
        return ans;
    }
}