#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using ll = long long;
using namespace atcoder;
using mint = modint;
int main() {
	mint::set_mod((ll)1e9 + 7);
	string S;cin >> S;
	int N = S.size();
	vector<mint> dp(N + 1, 0);
	mint ans = 0;
	vector<mint> T(26, 0);
	vector<mint> U(26, 0);
	for (int i = 1;i <= N;i++) {
		dp[i]++;
		int now = S[i - 1] - 'a';
		for (int c = 0;c < 26;c++) {
			dp[i] += T[c] + (c == now ? 0 : U[c]);
		}
		T[now] += dp[i];
		U[now] += mint(2).pow(i - 1);
		ans += dp[i];
	}
	cout << ans.val() << endl;
}