import java.util.ArrayDeque;
import java.util.Scanner;

public class LongestValidParentheses_03 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String text = scanner.nextLine();

        System.out.println(longestValidParentheses(text));
    }

    public static int longestValidParentheses(String s) {
        ArrayDeque<int[]> stack = new ArrayDeque<>();
        int result = 0;

        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == ')') {
                if (!stack.isEmpty() && stack.peek()[0] == 0) {
                    stack.pop();
                    result = Math.max(result, i - (stack.isEmpty() ? -1 : stack.peek()[1]));
                } else {
                    stack.push(new int[]{1, i});
                }
            } else {
                stack.push(new int[]{0, i});
            }
        }

        return result;
    }
}