#include <bits/stdc++.h>
using namespace std;
long long int f(long long int a) {
  long long int i, r = 0;
  for (i = 1; i <= a; i++) {
    r += i * (9 * (pow(10, i - 1)));
  }
  return r;
}
int main() {
  long long int i, n, a;
  cin >> n;
  for (i = 1; n % (long long int)(pow(10, i)) != n; i++)
    ;
  a = f(i - 1);
  n = n - (pow(10, i - 1));
  a = a + ((n + 1) * (i));
  cout << a;
}
