#include <iostream>
#include <string>

using namespace std;
typedef long long ll;
ll mod = 1000000007,ans = 0;
ll solve[200010],solve2[200010],sum[30] = {};
int main(){
    string s; cin >> s;
    int i,n = s.size();
    ll inv = (mod + 1)/2;
    solve[0] = 1; solve2[0] = 1;
    for(i=1;i<=n;i++) solve[i] = inv*solve[i - 1]%mod;
    for(i=1;i<=n;i++) solve2[i] = 2*solve2[i - 1]%mod;
    for(i=0;i<n;i++){
        int j = s[i] - 'a';
        (ans += (1 - solve[i]*sum[j]%mod + mod)%mod*inv%mod) %= mod;
        sum[j] += solve2[i];
    }
    cout << ans*solve2[n]%mod << endl;
}