#include <iostream>
#include <iomanip>
#include <algorithm>
#include <array>
#include <cassert>
#include <utility>
#include <vector>

constexpr int mod = 1'000'000'007;
constexpr int alpha_size = 'z' - 'a' + 1;

int main(void){
    std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); 
    std::cout << std::fixed << std::setprecision(16);
    
    std::string S; std::cin >> S;

    const int n = S.size();

    long long int res = 0, sum_dp = 0, sum_count = 1;

    std::array<long long int, alpha_size> count, dp;
    std::fill(count.begin(), count.end(), 0);
    std::fill(dp.begin(), dp.end(), 0);

    for(int i = 0; i < n; ++i){
        const int kind = S[i] - 'a';

        const long long int next_count = (count[kind] + sum_count) % mod;
        const long long int next_dp = (sum_dp + sum_count - count[kind]) % mod;

        (sum_count *= 2) %= mod;
        (sum_dp += next_dp) %= mod;

        count[kind] = next_count;
        (dp[kind] += next_dp) %= mod;
    }

    for(int i = 0; i < alpha_size; ++i) res += dp[i];
    res %= mod; if(res < 0) res += mod;
    std::cout << res << '\n';

    return 0;
}