c

int main() {
	int n;
	cin >> n;

	int isValid = 0;
	map<int, int> needsLeft;
	map<int, int> needsRight;

	for (int i = 0; i < n; i++) {
		string brackets;
		cin >> brackets;
		int left, right;
		left = right = 0;

		int startsWithRight, endsWithLeft;
		startsWithRight = brackets[0] == ')';
		endsWithLeft = brackets[brackets.size()-1] == '(';
		for (auto &c: brackets) {
			if (c == '(') {
				left++;
			} else {
				right++;
			}
		}

		// if starts w right and ends with left, paring wont create a valid 
		// sequence
		if (!(startsWithRight && endsWithLeft)) {
			int diff = abs(left - right);
			if (left > right) {
				needsRight[diff]++;
			} else if (right > left) {
				needsLeft[diff]++;
			} else {
				isValid++;
			}
		}
	}

	int cont = isValid / 2;

	map<int, int>::iterator it;
	for (it = needsLeft.begin(); it != needsLeft.end(); it++) {
		if (needsRight[it->first] > 0) {
			cont += min(it->second, needsRight[it->first]);
		}
	}

	cout << cont << endl;

	return 0;
}