/*

     水题：求总数字个数，开long long竟然莫名其妙WA了几次，也没改啥又对了:)

 */

 #include <cstdio>

 #include <iostream>

 #include <algorithm>

 #include <cstring>

 #include <cmath>

 #include <vector>

 #include <string>

 #include <queue>

 #include <map>

 #include <set>

 using namespace std;

 typedef long long ll;

 const int MAXN = 1e2 + ;

 const int INF = 0x3f3f3f3f;

 int main(void)      //Codeforces Round #308 (Div. 2) B. Vanya and Books

 {

     // freopen ("B.in", "r", stdin);

     ll n;

     while (scanf ("%I64d", &n) == )

     {

         int len = ;    ll tmp = n;

         while (tmp)

         {

             tmp /= ;    len++;

         }

         ll ans = ;    ll x = ;

         for (int i=; i<=len-; ++i)

         {

             ans += x * i;    x *= ;

         }

         ll y = ;

         for (int i=; i<=len-; ++i)    y *= ;

         ans += (n - y + ) * len;

         printf ("%I64d\n", ans);

     }

     return ;

 }