#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:66777216")
#pragma hdrstop
using namespace std;
inline void sIO() {}
inline void iIO() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
inline void fIO(string fn) {
  freopen((fn + ".in").c_str(), "r", stdin);
  freopen((fn + ".out").c_str(), "w", stdout);
}
inline void TM() {}
inline void swap(short& a, short& b) { b ^= a ^= b ^= a; }
inline void swap(int& a, int& b) { b ^= a ^= b ^= a; }
inline void swap(char& a, char& b) { b ^= a ^= b ^= a; }
inline void swap(long long& a, long long& b) { b ^= a ^= b ^= a; }
template <class T>
inline T abs(T x) {
  return x < 0 ? -x : x;
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline T min(T& a, T& b) {
  return a < b ? a : b;
}
template <class T>
inline T max(T& a, T& b) {
  return a > b ? a : b;
}
template <class T>
inline T gcd(T a, T b) {
  if (a < b) swap(a, b);
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
template <class T>
inline T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
template <class T>
inline bool isPrime(T n) {
  if (n < 2) return false;
  T kk = (T)sqrt(n + 0.);
  for (T i = 2; i <= kk; ++i)
    if (!(n % i)) return false;
  return true;
}
template <class T>
inline string toa(T x) {
  stringstream ss;
  ss << x;
  string ret;
  ss >> ret;
  return ret;
}
template <class T>
inline T ppow(T a, long long b) {
  T ret = 1;
  while (b) {
    if (b & 1) ret *= a;
    a *= a;
    b >>= 1;
  }
  return ret;
}
template <class T>
inline T ppow(T a, long long b, long long md) {
  T ret = 1;
  a %= md;
  while (b) {
    if (b & 1) ret = ret * a % md;
    a = a * a % md;
    b >>= 1;
  }
  return ret % md;
}
inline int toi(string s) {
  stringstream ss;
  ss << s;
  int ret;
  ss >> ret;
  return ret;
}
inline long long tol(string s) {
  stringstream ss;
  ss << s;
  long long ret;
  ss >> ret;
  return ret;
}
inline int Random() { return ((rand() << 16) | rand()); }
inline char upperCase(char ch) {
  return (ch >= 'a' && ch <= 'z') ? ch ^ 32 : ch;
}
inline char lowerCase(char ch) {
  return (ch >= 'A' && ch <= 'Z') ? ch ^ 32 : ch;
}
inline string upperCase(string s) {
  int ls = s.length();
  for (int i = 0; i < ls; ++i)
    if (s[i] >= 'a' && s[i] <= 'z') s[i] ^= 32;
  return s;
}
inline string lowerCase(string s) {
  int ls = s.length();
  for (int i = 0; i < ls; ++i)
    if (s[i] >= 'A' && s[i] <= 'Z') s[i] ^= 32;
  return s;
}
inline int dig(char ch) { return ch - 48; }
inline bool isAlpha(char ch) {
  return (ch >= 'A' && ch <= 'Z' || ch >= 'a' && ch <= 'z');
}
inline bool isDigit(char ch) { return (ch >= '0' && ch <= '9'); }
inline bool isLowerCase(char ch) { return (ch >= 'a' && ch <= 'z'); }
inline bool isUpperCase(char ch) { return (ch >= 'A' && ch <= 'Z'); }
int __;
const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-9;
const int MD = 1000000007;
int n, ls, cc;
char s[111111], ans[111111];
int main() {
  sIO();
  gets(s);
  ls = strlen(s);
  cc = 0;
  ans[0] = s[0];
  for (int i = 1; i < ls; ++i) {
    while (cc >= 0 && ans[cc] < s[i]) --cc;
    ans[++cc] = s[i];
  }
  for (int i = 0; i <= cc; ++i) putchar(ans[i]);
  return 0;
}

### Prompt

Your challenge is to write a cpp solution to the following problem:

You've got string s, consisting of only lowercase English letters. Find its lexicographically maximum subsequence.

We'll call a non-empty string s[p1p2... pk] = sp1sp2... spk(1 ≤ p1 < p2 < ... < pk ≤ |s|) a subsequence of string s = s1s2... s|s|.

String x = x1x2... x|x| is lexicographically larger than string y = y1y2... y|y|, if either |x| > |y| and x1 = y1, x2 = y2, ... , x|y| = y|y|, or exists such number r (r < |x|, r < |y|), that x1 = y1, x2 = y2, ... , xr = yr and xr + 1 > yr + 1. Characters in lines are compared like their ASCII codes.

Input

The single line contains a non-empty string s, consisting only of lowercase English letters. The string's length doesn't exceed 105.

Output

Print the lexicographically maximum subsequence of string s.

Examples

Input

ababba


Output

bbba


Input

abbcbccacbbcbaaba


Output

cccccbba

Note

Let's look at samples and see what the sought subsequences look like (they are marked with uppercase bold letters).

The first sample: aBaBBA

The second sample: abbCbCCaCbbCBaaBA

### Response

```cpp
#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:66777216")
#pragma hdrstop
using namespace std;
inline void sIO() {}
inline void iIO() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
inline void fIO(string fn) {
  freopen((fn + ".in").c_str(), "r", stdin);
  freopen((fn + ".out").c_str(), "w", stdout);
}
inline void TM() {}
inline void swap(short& a, short& b) { b ^= a ^= b ^= a; }
inline void swap(int& a, int& b) { b ^= a ^= b ^= a; }
inline void swap(char& a, char& b) { b ^= a ^= b ^= a; }
inline void swap(long long& a, long long& b) { b ^= a ^= b ^= a; }
template <class T>
inline T abs(T x) {
  return x < 0 ? -x : x;
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline T min(T& a, T& b) {
  return a < b ? a : b;
}
template <class T>
inline T max(T& a, T& b) {
  return a > b ? a : b;
}
template <class T>
inline T gcd(T a, T b) {
  if (a < b) swap(a, b);
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
template <class T>
inline T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
template <class T>
inline bool isPrime(T n) {
  if (n < 2) return false;
  T kk = (T)sqrt(n + 0.);
  for (T i = 2; i <= kk; ++i)
    if (!(n % i)) return false;
  return true;
}
template <class T>
inline string toa(T x) {
  stringstream ss;
  ss << x;
  string ret;
  ss >> ret;
  return ret;
}
template <class T>
inline T ppow(T a, long long b) {
  T ret = 1;
  while (b) {
    if (b & 1) ret *= a;
    a *= a;
    b >>= 1;
  }
  return ret;
}
template <class T>
inline T ppow(T a, long long b, long long md) {
  T ret = 1;
  a %= md;
  while (b) {
    if (b & 1) ret = ret * a % md;
    a = a * a % md;
    b >>= 1;
  }
  return ret % md;
}
inline int toi(string s) {
  stringstream ss;
  ss << s;
  int ret;
  ss >> ret;
  return ret;
}
inline long long tol(string s) {
  stringstream ss;
  ss << s;
  long long ret;
  ss >> ret;
  return ret;
}
inline int Random() { return ((rand() << 16) | rand()); }
inline char upperCase(char ch) {
  return (ch >= 'a' && ch <= 'z') ? ch ^ 32 : ch;
}
inline char lowerCase(char ch) {
  return (ch >= 'A' && ch <= 'Z') ? ch ^ 32 : ch;
}
inline string upperCase(string s) {
  int ls = s.length();
  for (int i = 0; i < ls; ++i)
    if (s[i] >= 'a' && s[i] <= 'z') s[i] ^= 32;
  return s;
}
inline string lowerCase(string s) {
  int ls = s.length();
  for (int i = 0; i < ls; ++i)
    if (s[i] >= 'A' && s[i] <= 'Z') s[i] ^= 32;
  return s;
}
inline int dig(char ch) { return ch - 48; }
inline bool isAlpha(char ch) {
  return (ch >= 'A' && ch <= 'Z' || ch >= 'a' && ch <= 'z');
}
inline bool isDigit(char ch) { return (ch >= '0' && ch <= '9'); }
inline bool isLowerCase(char ch) { return (ch >= 'a' && ch <= 'z'); }
inline bool isUpperCase(char ch) { return (ch >= 'A' && ch <= 'Z'); }
int __;
const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-9;
const int MD = 1000000007;
int n, ls, cc;
char s[111111], ans[111111];
int main() {
  sIO();
  gets(s);
  ls = strlen(s);
  cc = 0;
  ans[0] = s[0];
  for (int i = 1; i < ls; ++i) {
    while (cc >= 0 && ans[cc] < s[i]) --cc;
    ans[++cc] = s[i];
  }
  for (int i = 0; i <= cc; ++i) putchar(ans[i]);
  return 0;
}

```