sum of all possible sub-strings of this string.

#include <bits/stdc++.h>

using namespace std;
#define ll long long int

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    string s;
    cin >> s;
    ll n = s.size();
    ll dp[n] = {0};
    ll mod = 1e9+7;
    ll res = s[0] - '0';
    dp[0] = s[0] - '0';
    for (int i = 1; i < n; i++) {
        dp[i] = (((i + 1) * (s[i] - '0')) + (10 * dp[i - 1])) % mod;
        res += dp[i]%mod;
        res %= mod;
    }
    cout << res;

    return 0;
}