#include <bits/stdc++.h>
int main(int argc, char *argv[]) {
  int i, j;
  unsigned long long n, result, a[10];
  a[0] = 0;
  a[1] = 9;
  for (i = 2; i <= 9; i++) a[i] = a[i - 1] * 10 + 9;
  scanf("%llu", &n);
  result = 0;
  i = 9;
  ;
  while (n < a[i]) i--;
  result = result + (n - a[i]) * (i + 1);
  for (j = 1; j <= i; j++) result = result + (a[j] - a[j - 1]) * j;
  printf("%llu", result);
  return 0;
}
