#ifdef LOCAL #define _GLIBCXX_DEBUG #endif #include using namespace std; #define rep(i,s,t) for(ll i = (ll)(s); i < (ll)(t); i++) #define rrep(i,s,t) for(ll i = (ll)(s-1);(ll)(t) <= i; i--) #define all(x) (x).begin(), (x).end() typedef long long ll; typedef long double ld; typedef pair Pll; typedef vector vl; typedef vector vvl; typedef vector vvvl; constexpr ll INF = numeric_limits::max()/4; constexpr ll n_max = 2e5+10; #define int ll template string to_string(pair p); string to_string(const string &s) {return '"' + s + '"';} string to_string(const char *c) {return to_string((string) c);} string to_string(bool b) {return (b ? "true" : "false");} template string to_string(bitset v){ string res = ""; for(size_t i = 0; i < N; i++) res += static_cast('0' + v[i]); return res; } template string to_string(A v) { bool first = true; string res = "{"; for(const auto &x : v) { if(!first) res += ", "; first = false; res += to_string(x); } res += "}"; return res; } template string to_string(pair p){return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";} void debug_out() {cerr << endl;} template void debug_out(Head H, Tail... T) { cerr << " " << to_string(H); debug_out(T...); } #ifdef LOCAL #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__) #else #define debug(...) 42 #endif template bool chmax(T &a, T b){if(a < b){a = b; return true;} return false;} template bool chmin(T &a, T b){if(a > b){a = b; return true;} return false;} template class modint { using i64 = int_fast64_t; public: i64 a; constexpr modint(const i64 x = 0) noexcept { this -> a = x % Modulus; if(a < 0){ a += Modulus; } } constexpr int getmod() { return Modulus; } constexpr modint operator - () const noexcept { return a ? Modulus - a : 0; } constexpr const i64 &value() const noexcept {return a;} constexpr modint operator+(const modint rhs) const noexcept { return modint(*this) += rhs; } constexpr modint operator-(const modint rhs) const noexcept { return modint(*this) -= rhs; } constexpr modint operator*(const modint rhs) const noexcept { return modint(*this) *= rhs; } constexpr modint operator/(const modint rhs) const noexcept { return modint(*this) /= rhs; } constexpr modint &operator+=(const modint rhs) noexcept { a += rhs.a; if(a >= Modulus) { a -= Modulus; } return *this; } constexpr modint &operator-=(const modint rhs) noexcept { if(a < rhs.a) { a += Modulus; } a -= rhs.a; return *this; } constexpr modint &operator*=(const modint rhs) noexcept { a = a * rhs.a % Modulus; return *this; } constexpr modint &operator/=(modint rhs) noexcept { i64 a_ = rhs.a, b = Modulus, u = 1, v = 0; while(b){ i64 t = a_/b; a_ -= t * b; swap(a_,b); u -= t * v; swap(u,v); } a = a * u % Modulus; if(a < 0) a += Modulus; return *this; } // 自前実装 constexpr bool operator==(const modint rhs) noexcept { return a == rhs.a; } constexpr bool operator!=(const modint rhs) noexcept { return a != rhs.a; } constexpr bool operator>(const modint rhs) noexcept { return a > rhs.a; } constexpr bool operator>=(const modint rhs) noexcept { return a >= rhs.a; } constexpr bool operator<(const modint rhs) noexcept { return a < rhs.a; } constexpr bool operator<=(const modint rhs) noexcept { return a <= rhs.a; } constexpr modint& operator++() noexcept { return (*this) += modint(1); } // constexpr modint operator++(int) { // modint tmp(*this); // operator++(); // return tmp; // } constexpr modint& operator--() noexcept { return (*this) -= modint(1); } // constexpr modint operator--(int) { // modint tmp(*this); // operator--(); // return tmp; // } template friend constexpr modint modpow(const modint &mt, T n) noexcept { if(n < 0){ modint t = (modint(1) / mt); return modpow(t, -n); } modint res = 1, tmp = mt; while(n){ if(n & 1)res *= tmp; tmp *= tmp; n /= 2; } return res; } friend constexpr string to_string(const modint &mt) noexcept { return to_string(mt.a); } }; // 標準入出力対応 template std::ostream &operator<<(std::ostream &out, const modint &m) { out << m.a; return out; } template std::istream &operator>>(std::istream &in, modint &m) { ll a; in >> a; m = modint(a); return in; } const ll MOD = 1e9+7; // const ll MOD = 998244353; using mint = modint; signed main(){ cin.tie(nullptr); ios::sync_with_stdio(false); string s;cin >> s; ll n = s.size(); // vector cnt(n + 1, vector(26)); // rep(i,0,n){ // ll t = s[i] - 'a'; // cnt[i+1][t]++; // rep(j,0,26){ // cnt[i+1][j] += cnt[i][j]; // } // } vector dp(26); mint ans = 0; rep(i,0,n){ ll t = s[i] - 'a'; ans += (modpow(mint(2), i) - dp[t]) * modpow(mint(2), n-i-1); dp[t] += modpow(mint(2), i); } cout << ans << "\n"; }