#include <bits/stdc++.h>
using namespace std;
int poww(int a, int b) {
  for (int i = 0; i < b; i++) a *= a;
  return a;
}
int main() {
  int n, t;
  cin >> n;
  if (n < 10) {
    cout << n << endl;
    return 0;
  }
  long long i = 2;
  long long sum = 9;
  long long x = 10, v[] = {999999999, 99999999, 9999999, 999999, 99999, 9999,
                           999,       99,       9,       0,      0};
  reverse(v, v + 11);
  for (int i = 10; i > 1; i--) {
    if (n - v[i] > 0) {
      sum += (n - v[i]) * i;
      n -= (n - v[i]);
    }
  }
  cout << sum << endl;
  return 0;
}
