#include <iostream>
#include <string>
using namespace std;
bool search(string s, char a)
{
	for (int i = 0; i < s.size(); i++)
		if (s[i] == a)
			return true;
	return false;
}
int main()
{
	string s;
	while (cin>>s)
	{
		for (char i = '9'; i >= '0'; i--)
		{
			int j = 0;
			bool b = false;
			while (1)
			{
				if (s[j] == i)
				{
					if (b)
					{
						s.erase(j,1);
						j--;
					}
					else
					{
						if (s[j] < s[j + 1] && search(s.substr(j+1),i))
						{
							s.erase(j,1);
							j--;
						}
						else
							b = true;
					}
				}
				j++;
				if (j >= (s.length() - 1))
				{
					if (b&&s[j]==i)
						s.erase(j,1);
					break;
				}
			}			
		}
		cout << s << endl;
	}
}