#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
const int mod = 1000000007;
const double pi = acos(-1);
inline void gn(long long& x) {
  int sg = 1;
  char c;
  while (((c = getchar()) < '0' || c > '9') && c != '-')
    ;
  c == '-' ? (sg = -1, x = 0) : (x = c - '0');
  while ((c = getchar()) >= '0' && c <= '9') x = x * 10 + c - '0';
  x *= sg;
}
inline void gn(int& x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(unsigned long long& x) {
  long long t;
  gn(t);
  x = t;
}
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long powmod(long long a, long long x, long long mod) {
  long long t = 1ll;
  while (x) {
    if (x & 1) t = t * a % mod;
    a = a * a % mod;
    x >>= 1;
  }
  return t;
}
int main() {
  long long ans = 0;
  long long n;
  cin >> n;
  for (long long i = 1; i <= 10; ++i) {
    long long low = (int)(pow(10, i - 1) + eps);
    if (low > n) {
      cout << ans << endl;
      return 0;
    }
    long long up = ((n) < (low * 10 - 1) ? (n) : (low * 10 - 1));
    ans += ((up - low + 1) * i);
  }
  cout << ans << endl;
  return 0;
}
