class TreeNode {

public:

bool flag;

TreeNode* left, *right;

TreeNode() : flag(false), left(nullptr), right(nullptr) {};

};

int getAns(vector<string> &str) {

root = new TreeNode();

for (const string& s : str) insert(s);

dfs(root);

return answer;

}

TreeNode* root;

int answer = 0;

void insert(const string& s) {

TreeNode* cur = root;

for (const char ch : s) {

TreeNode** target = nullptr;

if (ch == '0') target = &(cur->left);

else target = &(cur->right);

if (*target == nullptr) *target = new TreeNode();

cur = *target;

}

cur->flag = true;

}

int dfs(TreeNode* u) {

if (u == nullptr) return 0;

int left = dfs(u->left);

int right = dfs(u->right);

if (left && right) answer = max(answer, left + right);

if (u->flag && left) answer = max(answer, left);

if (u->flag && right) answer = max(answer, right);

return max(left, right) + 1;

}