#include <bits/stdc++.h>
#include <atcoder/segtree>
#include <atcoder/modint>
using namespace std;
const int M = 26;
constexpr int md = 1e9 + 7;
using mint = atcoder::static_modint<md>;
struct Monoid {
	mint sum, cnt;
	static Monoid op(Monoid a, Monoid b) {
		return Monoid{a.sum + b.sum, a.cnt + b.cnt};
	}
	static Monoid e() {
		return Monoid{0, 0};
	}
};

int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(nullptr);
	string S;
	cin >> S;
	atcoder::segtree<Monoid, Monoid::op, Monoid::e> dp(M);
	for(char ch: S) {
		Monoid cur = dp.get(ch - 'a');
		Monoid all = dp.all_prod();
		all.sum -= cur.sum;
		all.cnt -= cur.cnt;
		cur.sum *= 2, cur.cnt *= 2;
		cur.sum += all.sum + all.cnt;
		cur.cnt += all.cnt;
		cur.sum += 1, cur.cnt += 1;
		dp.set(ch - 'a', cur);
	}
	mint ans = dp.all_prod().sum;
	cout << ans.val() << "\n";
}