text: /* Reference(s): --->
     https://www.geeksforgeeks.org/count-distinct-subsequences/
     https://www.youtube.com/watch?v=9UEHPiK53BA  
     https://leetcode.com/problems/distinct-subsequences-ii/            
  */
  
  #include<bits/stdc++.h>
  using namespace std;
  
  #define ll long long
  #define ld long double
  #define ull unsigned long long
  #define pb push_back
  #define ppb pop_back
  #define mp make_pair
  #define F first
  #define S second
  #define PI 3.1415926535897932384626
  #define sz(x) ((int)(x).size())
  
  typedef pair<int, int> pii;
  typedef pair<ll, ll> pll;
  typedef vector<int> vi;
  typedef vector<ll> vll;
  typedef vector<ull> vull;
  typedef vector<bool> vb;
  typedef vector<char> vc;
  typedef vector<pii> vpii;
  typedef vector<pll> vpll;
  typedef vector<vi> vvi;
  typedef vector<vll> vvll;
  typedef vector<vull> vvull;
  typedef vector<vb> vvb;
  typedef vector<vc> vvc;
  
  /************************************************** DEBUGGER *******************************************************************************************************/
  
  #ifndef ONLINE_JUDGE
  #define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
  #else
  #define debug(x)
  #endif
  
  void _print(ll t) { cerr << t; }
  void _print(int t) { cerr << t; }
  void _print(string t) { cerr << t; }
  void _print(char t) { cerr << t; }
  void _print(ld t) { cerr << t; }
  void _print(double t) { cerr << t; }
  void _print(ull t) { cerr << t; }
  
  template <class T, class V> void _print(pair <T, V> p);
  template <class T> void _print(vector <T> v);
  template <class T> void _print(vector <vector<T>> v);
  template <class T> void _print(set <T> v);
  template <class T, class V> void _print(map <T, V> v);
  template <class T> void _print(multiset <T> v);
  template <class T, class V> void _print(pair <T, V> p) { cerr << "{"; _print(p.F); cerr << ","; _print(p.S); cerr << "}"; }
  template <class T> void _print(vector <T> v) { cerr << "[ "; for (T i : v) {_print(i); cerr << " "; } cerr << "]"; }
  template <class T> void _print(vector <vector<T>> v) { cerr << "==>" << endl; for (vector<T> vec : v) { for(T i : vec) {_print(i); cerr << " "; } cerr << endl; } }
  template <class T> void _print(set <T> v) { cerr << "[ "; for (T i : v) {_print(i); cerr << " "; } cerr << "]"; }
  template <class T> void _print(multiset <T> v) { cerr << "[ "; for (T i : v) {_print(i); cerr << " "; } cerr << "]"; }
  template <class T, class V> void _print(map <T, V> v) { cerr << "[ "; for (auto i : v) {_print(i); cerr << " "; } cerr << "]"; }
  
  /*******************************************************************************************************************************************************************/
  
  mt19937_64 rang(chrono::high_resolution_clock::now().time_since_epoch().count());
  int rng(int lim) {
      uniform_int_distribution<int> uid(0,lim-1);
      return uid(rang);
  }
  
  const int INF = 0x3f3f3f3f;
  const int mod = 1e9+7;
  
  ll mod_exp(ll a, ll b) { a %= mod; if(a == 0) return 0LL; ll res = 1LL; 
                           while(b > 0) { if(b & 1) res = (res * a) % mod; a = (a * a) % mod; b >>= 1; } return res; }
                           
  ll mod_inv(ll a) { return mod_exp(a, mod - 2); } // works only for prime value of "mod"
  ll GCD(ll a, ll b) { return (b == 0) ? a : GCD(b, a % b); }
  
  /******************************************************************************************************************************/
  
  // dp[i] store the count of distinct subseq. in prefix
  // of length i (i.e. for s[0......i-1])
  vll dp;
  
  // map to store index of last occurrence of a char
  unordered_map<char, int> um;
  
  // Returns count of distinct sunsequences (including empty subseq) of 's'
  ll cnt_dis_seq(string &s) {
  	int n = s.length();
  	dp.clear();
  	dp.resize(n + 1);
  	
  	// Empty string has only one subsequence
  	dp[0] = 1;
  	
  	// Traverse through all lengths from 1 to n.
  	for(int i = 1; i <= n; i++) {
  		char ch = s[i-1];
  		dp[i] = 2 * dp[i-1];
  		
  		// If current char has appeared before, then remove all 
  		// subseq ending with previous occurrence.
  		if(um.count(ch)) {
  			dp[i] -= dp[um[ch] - 1];
  		}
  		
  		// Mark occurrence of current character
  		um[ch] = i;
  	}
  	
  	return dp[n];
  }
  
  void solve()
  {
    	string s; cin >> s;
    	cout << cnt_dis_seq(s) << "\n";
  }
  
  int main()
  {
      ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
      srand(chrono::high_resolution_clock::now().time_since_epoch().count());
  
      // #ifndef ONLINE_JUDGE
      //     freopen("input.txt", "r", stdin);
      //     freopen("output.txt", "w", stdout);
      // #endif
      
      // #ifndef ONLINE_JUDGE
      //      freopen("error.txt", "w", stderr);
      // #endif
      
      int t = 1;
      // int test = 1;
      // cin >> t;
      while(t--) {
          // cout << "Case #" << test++ << ": ";
          solve();
      }
  
      return 0;
  }
  
  // Time Complexity: O(n) 
  // Auxiliary Space: O(n)