import java.util.ArrayList;
import java.util.List;

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * public interface NestedInteger {
 *
 *     // @return true if this NestedInteger holds a single integer,
 *     // rather than a nested list.
 *     public boolean isInteger();
 *
 *     // @return the single integer that this NestedInteger holds,
 *     // if it holds a single integer
 *     // Return null if this NestedInteger holds a nested list
 *     public Integer getInteger();
 *
 *     // @return the nested list that this NestedInteger holds,
 *     // if it holds a nested list
 *     // Return null if this NestedInteger holds a single integer
 *     public List<NestedInteger> getList();
 * }
 */

public class T22 {
    // @param nestedList a list of NestedInteger
    // @return a list of integer
//    public List<Integer> flatten(List<NestedInteger> nestedList) {
//        // Write your code here
//        List<Integer> result = new ArrayList<Integer>();
//        for (NestedInteger nes: nestedList) {
//            if (nes.isInteger()) {
//                result.add(nes.getInteger());
//            } else {
//                result.addAll(flatten(nes.getList()));
//            }
//        }
//        return result;
//    }
}