//字符串中找出连续最长的数字串

import java.util.Scanner;
//字符串中找出连续最长的数字串
public class Main_831 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        while (scanner.hasNext()) {
            String str = scanner.nextLine();
            String[] numArr = str.split("[^0-9]+");
            int max = 0;
            String res = "";
            for (int i = 0; i < numArr.length; i++) {
                int len = numArr[i].length();
                if (len > max) {
                    res = numArr[i];
                    max = len;
                }
            }
                System.out.println(res);
        }
        scanner.close();
    }
}