import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            String s = in.nextLine();
            String cur = "";
            String res = "";
            int len = s.length();
            int i = 0;
            for( i = 0; i < len; i++) {
                char ch = s.charAt(i);
                if(ch >= '0' && ch <= '9') {
                    cur += ch + "";
                } else {
                    if(cur.length() > res.length()) {
                        res = cur;
                    } else {
                        cur = "";
                    }
                }
            }
            if(i == len && cur.length() > res.length()) {
                res = cur;
            }
            System.out.print(res);
        }
         
    }
}