#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using mint = modint1000000007;

int main() {
    string s;
    cin >> s;
    int n = s.size();
    
    vector<mint> two(n+1, 1);
    rep(i, n) two[i+1] = two[i]*2;
    
    mint ans;
    vector<mint> dp(26);
    rep(i, n) {
        ans += (two[i]-dp[s[i]-'a']) * two[n-1-i];
        dp[s[i]-'a'] += two[i];
    }
    
    cout << ans.val() << '\n';
    
    return 0;
}