这是我根据problemset的trie tree写的程序，本地编译得到的结果是正确的但是在平台上遇到run time error的问题，请问是什么问题啊，是python编写的

class TrieTree(object):

 def __init__(self):
        self.tree={}

    def add(self,word):
        tree=self.tree
        key=[]
        for char in word:
            if char in tree:
                tree=tree[char]
                key.append(char)
            else:
                tree[char]={}
                tree=tree[char]
                tree['l']=0
        tree=self.tree
        for char in key:
            tree=tree[char]
            tree['l']=tree['l']+1

    def search(self,word):
        i=0
        tree=self.tree
        for char in word:
            if char in tree:
                tree=tree[char]
            else:
                i=1
                break
        if i==1:
            print 0
        else:
            print tree['l']+1

tree=TrieTree()

for i in range(int(raw_input())):
    tree.add(raw_input())

for i in range(int(raw_input())):
    tree.search(raw_input())