#include <bits/stdc++.h>   using namespace std;   template <typename Arg1>   void __f(const char* name, Arg1&& arg1) {     cerr << name <<   :   << arg1 << std::endl;   }   template <typename Arg1, typename... Args>   void __f(const char* names, Arg1&& arg1, Args&&... args) {     const char* comma = strchr(names + 1,  , );     cerr.write(names, comma - names) <<   :   << arg1 <<   |  ;     __f(comma + 1, args...);   }   const int mod = int(1e9) + 7;   const int N = int(1e6) + 7;   long long int two[N];   void pre() {     two[0] = 1;     for (int i = (int)1; i < (int)N; i++) {       two[i] = (two[i - 1] * 2) % mod;     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     pre();     string s;     cin >> s;     int cnt = 0;     long long int ans = 0;     for (int i = (int)0; i < (int)(int)(s.size()); i++) {       if (s[i] ==  b ) {         ans = (ans + (two[cnt] - 1)) % mod;         continue;       }       cnt++;     }     cout << ans << endl;     return 0;   }   