CntSubsirMax

#include <bits/stdc++.h>
#define int long long

using namespace std;

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    string s;
    cin >> s;
    int N = s.size();
    s = '0' + s;
    vector<int> st(N + 1, 0);
    stack<int> S;
    for(int i = N; i > 0; --i) {
        while(!S.empty() && s[S.top()] <= s[i]) {
            st[S.top()] = i;
            S.pop();
        }
        S.emplace(i);
    }
    const int mod = 1e9 + 7;
    vector<int> dp(N + 1), sum(N + 1);
    for(int i = 1; i <= N; ++i) {
        sum[i] = (sum[st[i]] + i - st[i]) % mod;
        dp[i] = (dp[st[i]] + sum[i]) % mod;
    }
    int ans = 0;
    for(int i = 1; i <= N; ++i)
        ans = (ans + dp[i]) % mod;
    cout << ans;
}