#include <bits/stdc++.h>
using namespace std;
template <class T>
void pp(T v) {
  for (__typeof((v).begin()) it = (v).begin(); it != (v).end(); ++it)
    cout << *it << ' ';
  cout << endl;
}
template <class T>
void pp(T v, int n) {
  for (int i = 0; i < (int)n; i++) cout << v[i] << ' ';
  cout << endl;
}
template <class T>
inline void chmax(T &a, const T b) {
  a = max(a, b);
}
template <class T>
inline void chmin(T &a, const T b) {
  a = min(a, b);
}
const int INF = 1 << 28;
const double EPS = 1.0e-9;
static const int dx[] = {1, 0, -1, 0}, dy[] = {0, -1, 0, 1};
int main(void) {
  string ans = "", input;
  cin >> input;
  vector<int> right(256, -1);
  for (int i = 0; i < (int)input.size(); i++) {
    char c = input[i];
    right[c] = i;
  }
  int old = 0;
  for (int c = 'z'; c >= 'a'; c--) {
    if (right[c] == -1) continue;
    if (right[c] >= old) {
      for (int i = old; i <= right[c]; i++) {
        if (input[i] == (char)c) ans += (char)c;
      }
      chmax(old, right[c] + 1);
    }
  }
  cout << ans << endl;
  return 0;
}
