class Trie {

    Node root;
    /** Initialize your data structure here. */
    public Trie() {
        root = new Node();
    }

    /** Inserts a word into the trie. */
    public void insert(String word) {

        Node current = root;

        for (char c: word.toCharArray()) {
            if (current.children[c - 'a'] != null) {
                current.count++;
            } else {
                current.children[c - 'a'] = new Node();
            }
            current = current.children[c - 'a'];
        }
        current.isFinal = true;


    }

    /** Returns if the word is in the trie. */
    public boolean search(String word) {

        Node current = root;
        for (char c: word.toCharArray()) {
            if (current.children[c - 'a'] == null) {
                return false;
            }
            current = current.children[c - 'a'];
        }
        return current.isFinal;

    }

    /** Returns if there is any word in the trie that starts with the given prefix. */
    public boolean startsWith(String prefix) {
        Node current = root;
        for (char c: prefix.toCharArray()) {
            if (current.children[c - 'a'] == null) {
                return false;
            }
            current = current.children[c - 'a'];
        }
        return true;
    }

    static class Node {
        Node[] children;
        boolean isFinal;
        int count;

        public Node() {
            children = new Node[26];
        }
    }
}

/**
 * Your Trie object will be instantiated and called as such:
 * Trie obj = new Trie();
 * obj.insert(word);
 * boolean param_2 = obj.search(word);
 * boolean param_3 = obj.startsWith(prefix);
 */